{"id":524292,"date":"2026-07-16T02:19:23","date_gmt":"2026-07-16T06:19:23","guid":{"rendered":"https:\/\/www.fs1inc.com\/blog\/?p=524292"},"modified":"2026-07-19T11:11:43","modified_gmt":"2026-07-19T15:11:43","slug":"2003-chevrolet-blazer-pcm-replacement-guide","status":"publish","type":"post","link":"https:\/\/www.fs1inc.com\/blog\/2003-chevrolet-blazer-pcm-replacement-guide\/","title":{"rendered":"2003 Chevrolet Blazer PCM and ECM Guide: Replacement and Programming"},"content":{"rendered":"<div class=\"container\">\n<section class=\"hero\">\n<div class=\"code-badge\">PCM<\/div>\n<h1>2003 Chevrolet Blazer PCM and ECM Guide: Replacement and Programming<\/h1>\n<p class=\"hero-subtitle\">The Powertrain Control Module (PCM) or Engine Control Module (ECM) in your 2003 Chevrolet Blazer 4.3L is the main computer that manages engine and transmission operation. When it fails, you may experience no-start, stalling, or check-engine lights. Replacement requires careful handling and a relearn procedure.<\/p>\n<\/section>\n<div class=\"quick-summary\">\n<h2>Quick Summary<\/h2>\n<ul>\n<li>The PCM\/ECM controls fuel, spark, and transmission shift points in the 2003 Blazer 4.3L.<\/li>\n<li>Factory labor time for PCM replacement under the hood is 1.0 hour; under the instrument panel it is 1.8 hours.<\/li>\n<li>A 0.5-hour relearn procedure is required after installing a new module.<\/li>\n<li>Factory cautions stress turning the ignition OFF before disconnecting PCM connectors to avoid internal damage.<\/li>\n<li>Flagship One units arrive pre-programmed with your VIN, eliminating the need for a dealer relearn.<\/li>\n<\/ul>\n<\/div>\n<div class=\"info-section\">\n<p>If your 2003 Chevrolet Blazer 4.3L is experiencing a no-start condition, erratic shifting, or a persistent check-engine light, the Powertrain Control Module (PCM) or Engine Control Module (ECM) may be the culprit. This computer is the brain of your Blazer&#8217;s engine and transmission management system. Understanding what the module does, where it is located, and what replacement involves can help you make an informed repair decision. This guide covers the symptoms of a failing PCM, the factory-recommended replacement procedure, and how a pre-programmed unit from Flagship One can save you time and hassle. We will also review relevant factory service bulletins and internal trouble codes specific to this vehicle.<\/p>\n<\/div>\n<div class=\"info-section\">\n<h2>What the PCM Does in a 2003 Chevrolet Blazer<\/h2>\n<p>The Powertrain Control Module (PCM) in your 2003 Chevrolet Blazer 4.3L is a single computer that integrates engine and transmission control. It receives input from sensors such as the crankshaft position sensor, throttle position sensor, and oxygen sensors, then adjusts fuel delivery, ignition timing, and shift patterns accordingly. When the PCM fails, it can cause a wide range of drivability issues. For this vehicle, <a href=\"https:\/\/www.fs1inc.com\/gm\/chevrolet-pcm-ecm-ecu-engine-computer\/blazer-engine-computers.html\">replacement PCMs for the Blazer<\/a> are available as either new OEM units or remanufactured modules. The PCM is also referred to as the Engine Control Module (ECM) in some service literature, but they are the same component. A faulty PCM may trigger internal diagnostic trouble codes like P0601, indicating a memory checksum error, or P0706, which relates to the gear range indicator. Understanding the role of this module is key to diagnosing problems accurately.<\/p>\n<\/div>\n<div class=\"info-section\">\n<h2>Where the PCM Is Located and What Replacement Involves<\/h2>\n<p>The PCM\/ECM in the 2003 Chevrolet Blazer 4.3L can be located in one of two positions depending on the vehicle&#8217;s configuration. Under the hood, it is typically mounted near the driver-side firewall. Alternatively, it may be located under the instrument panel, inside the cabin. Factory labor time for removal and replacement is 1.0 hour if the module is under the hood, and 1.8 hours if it is under the instrument panel. After installing the new module, a 0.5-hour relearn procedure is required. The factory cautions that the ignition must be turned OFF when disconnecting or reconnecting the PCM connectors to prevent internal damage. Additionally, avoid touching connector pins or circuit board components to prevent electrostatic discharge damage.<\/p>\n<figure style=\"margin:22px auto;text-align:center;max-width:720px\"><img decoding=\"async\" style=\"max-width:100%;height:auto;border:1px solid #e2e6ec;border-radius:8px\" src=\"https:\/\/www.fs1inc.com\/blog\/wp-content\/uploads\/2026\/07\/2003-chevrolet-blazer-pcm-service-figure.webp\" alt=\"2003 Chevrolet Blazer PCM location diagram\" loading=\"lazy\"\/><figcaption style=\"font-size:13px;color:#667085;margin-top:8px\">From the factory PCM removal procedure for the 2003 Chevrolet Blazer.<\/figcaption><\/figure>\n<div style=\"background:#f7f9fc;border:1px solid #e2e8f2;border-radius:10px;padding:18px 24px;margin:18px 0\">\n<h3 style='margin-top:0'>How to Reach the PCM on the 2003 Chevrolet Blazer<\/h3>\n<ol style=\"margin:14px 0 6px 0;padding-left:26px\">\n<li style=\"margin:10px 0;line-height:1.65\"><b>Remove<\/b> any debris from the PCM connector surfaces before.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\"><b>Disconnect<\/b> the negative battery cable.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\"><b>Remove<\/b> the PCM from the PCM mounting bracket.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\"><b>Disconnect<\/b> the PCM electrical connectors.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\"><b>Remove<\/b> the replacement PCM from the packaging.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\"><b>Slide<\/b> the PCM retainer into the PCM bracket slots.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\"><b>Pull<\/b> the PCM retention bar into position.<\/li>\n<\/ol>\n<p style='margin:10px 0 0 0'><em>Work with the ignition off, and treat the module as static-sensitive: avoid touching the connector pins at any point.<\/em><\/p>\n<\/div>\n<table style=\"width:100%;border-collapse:collapse;margin:18px 0;font-size:15px\">\n<tr>\n<th style=\"border:1px solid #d6dbe3;background:#f2f5f9;padding:9px 12px;text-align:left\">Operation<\/th>\n<th style=\"border:1px solid #d6dbe3;background:#f2f5f9;padding:9px 12px;text-align:left\">Configuration<\/th>\n<th style=\"border:1px solid #d6dbe3;background:#f2f5f9;padding:9px 12px;text-align:left\">Book Time<\/th>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Powertrain Control Module R&amp;R<\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Under Hood<\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">1.0 hr<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Powertrain Control Module R&amp;R<\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Under Inst. Panel<\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">1.8 hr<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Powertrain Control Module Relearn<\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">All configurations<\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">0.5 hr<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Engine Control Module R&amp;R<\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Under Hood<\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">1.0 hr<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Engine Control Module R&amp;R<\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Under Inst. Panel<\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">1.8 hr<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Engine Control Module Relearn<\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">All configurations<\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">0.5 hr<\/td>\n<\/tr>\n<\/table>\n<\/div>\n<div class=\"info-section\">\n<h2>Programming Requirements After Replacement<\/h2>\n<p>After replacing the PCM\/ECM in your 2003 Chevrolet Blazer 4.3L, the factory procedure requires a 0.5-hour relearn process. This involves using a scan tool to program the module with the correct VIN and calibrations. However, when you purchase <a href=\"https:\/\/www.fs1inc.com\/2003-chevrolet-blazer-4-3l-engine-computer-pcm-ecm-ecu-programmed-plug-play.html\">a VIN-programmed replacement unit<\/a> from Flagship One, that step is already completed. The module arrives ready to install, with your vehicle&#8217;s specific software loaded. This eliminates the need for a dealer visit or specialized equipment. Simply install the module, reconnect the battery with the ignition off, and the vehicle should start and run normally. The factory cautions about turning the ignition off during connector handling still apply to prevent damage.<\/p>\n<\/div>\n<div class=\"info-section\">\n<h2>Symptoms of a Failing PCM<\/h2>\n<p>A failing PCM\/ECM in the 2003 Chevrolet Blazer 4.3L can produce a variety of symptoms. The engine may crank but not start, or it may stall unexpectedly while driving. You might notice erratic shifting, the gear range indicator reading incorrectly (for example, always showing &#8216;2&#8217; or &#8216;D2&#8217;), or the Service Engine Soon (SES) light illuminated. Diagnostic trouble codes such as <a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0601-internal-control-module-memory-checksum-error\/\">internal control module fault<\/a> may be stored. Other common issues include misfire codes, dead communication with a scan tool, and intermittent electrical problems. If you experience any of these symptoms, especially in combination, the PCM should be inspected. Factory service bulletin #04-07-30-029 addresses a no-start condition and incorrect gear range indicator related to PCM programming.<\/p>\n<\/div>\n<div class=\"info-section\">\n<h2>Module Trouble Codes on the 2003 Chevrolet Blazer<\/h2>\n<p>The following diagnostic trouble codes are documented as module-internal faults for the 2003 Chevrolet Blazer 4.3L. These codes indicate problems within the PCM\/ECM itself, such as memory errors, communication failures, or internal circuit malfunctions. They are listed here for reference when diagnosing a suspected module failure.<\/p>\n<table style=\"width:100%;border-collapse:collapse;margin:18px 0;font-size:15px\">\n<tr>\n<th style=\"border:1px solid #d6dbe3;background:#f2f5f9;padding:9px 12px;text-align:left\">Code<\/th>\n<th style=\"border:1px solid #d6dbe3;background:#f2f5f9;padding:9px 12px;text-align:left\">Meaning<\/th>\n<th style=\"border:1px solid #d6dbe3;background:#f2f5f9;padding:9px 12px;text-align:left\">Full Guide<\/th>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0601-internal-control-module-memory-checksum-error\/\" style=\"color:#0563C1;text-decoration:none;display:block;cursor:pointer\"><b>P0601<\/b><\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0601-internal-control-module-memory-checksum-error\/\" style=\"color:#1a2b49;text-decoration:none;display:block;cursor:pointer\">Internal memory checksum error<\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0601-internal-control-module-memory-checksum-error\/\" style=\"color:#0563C1\"><b><u>Full P0601 guide &rarr;<\/u><\/b><\/a><\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0602-control-module-programming-error\/\" style=\"color:#0563C1;text-decoration:none;display:block;cursor:pointer\"><b>P0602<\/b><\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0602-control-module-programming-error\/\" style=\"color:#1a2b49;text-decoration:none;display:block;cursor:pointer\">Control module programming error<\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0602-control-module-programming-error\/\" style=\"color:#0563C1\"><b><u>Full P0602 guide &rarr;<\/u><\/b><\/a><\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0603-internal-control-module-keep-alive-memory-kam-error\/\" style=\"color:#0563C1;text-decoration:none;display:block;cursor:pointer\"><b>P0603<\/b><\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0603-internal-control-module-keep-alive-memory-kam-error\/\" style=\"color:#1a2b49;text-decoration:none;display:block;cursor:pointer\">Keep-alive memory (KAM) error<\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0603-internal-control-module-keep-alive-memory-kam-error\/\" style=\"color:#0563C1\"><b><u>Full P0603 guide &rarr;<\/u><\/b><\/a><\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0604-internal-control-module-random-access-memory-ram-error\/\" style=\"color:#0563C1;text-decoration:none;display:block;cursor:pointer\"><b>P0604<\/b><\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0604-internal-control-module-random-access-memory-ram-error\/\" style=\"color:#1a2b49;text-decoration:none;display:block;cursor:pointer\">Internal RAM error<\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0604-internal-control-module-random-access-memory-ram-error\/\" style=\"color:#0563C1\"><b><u>Full P0604 guide &rarr;<\/u><\/b><\/a><\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0605-internal-control-module-read-only-memory-rom-error\/\" style=\"color:#0563C1;text-decoration:none;display:block;cursor:pointer\"><b>P0605<\/b><\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0605-internal-control-module-read-only-memory-rom-error\/\" style=\"color:#1a2b49;text-decoration:none;display:block;cursor:pointer\">Internal ROM error<\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0605-internal-control-module-read-only-memory-rom-error\/\" style=\"color:#0563C1\"><b><u>Full P0605 guide &rarr;<\/u><\/b><\/a><\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0606-control-module-processor\/\" style=\"color:#0563C1;text-decoration:none;display:block;cursor:pointer\"><b>P0606<\/b><\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0606-control-module-processor\/\" style=\"color:#1a2b49;text-decoration:none;display:block;cursor:pointer\">Module processor failure<\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0606-control-module-processor\/\" style=\"color:#0563C1\"><b><u>Full P0606 guide &rarr;<\/u><\/b><\/a><\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0607-control-module-performance\/\" style=\"color:#0563C1;text-decoration:none;display:block;cursor:pointer\"><b>P0607<\/b><\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0607-control-module-performance\/\" style=\"color:#1a2b49;text-decoration:none;display:block;cursor:pointer\">Module performance fault<\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0607-control-module-performance\/\" style=\"color:#0563C1\"><b><u>Full P0607 guide &rarr;<\/u><\/b><\/a><\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0608-control-module-vss-output\/\" style=\"color:#0563C1;text-decoration:none;display:block;cursor:pointer\"><b>P0608<\/b><\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0608-control-module-vss-output\/\" style=\"color:#1a2b49;text-decoration:none;display:block;cursor:pointer\">Module-internal fault<\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0608-control-module-vss-output\/\" style=\"color:#0563C1\"><b><u>Full P0608 guide &rarr;<\/u><\/b><\/a><\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0609-control-module-vss-output-b\/\" style=\"color:#0563C1;text-decoration:none;display:block;cursor:pointer\"><b>P0609<\/b><\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0609-control-module-vss-output-b\/\" style=\"color:#1a2b49;text-decoration:none;display:block;cursor:pointer\">Module-internal fault<\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0609-control-module-vss-output-b\/\" style=\"color:#0563C1\"><b><u>Full P0609 guide &rarr;<\/u><\/b><\/a><\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0641-sensor-reference-voltage-circuitopen\/\" style=\"color:#0563C1;text-decoration:none;display:block;cursor:pointer\"><b>P0641<\/b><\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0641-sensor-reference-voltage-circuitopen\/\" style=\"color:#1a2b49;text-decoration:none;display:block;cursor:pointer\">Module-internal fault<\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0641-sensor-reference-voltage-circuitopen\/\" style=\"color:#0563C1\"><b><u>Full P0641 guide &rarr;<\/u><\/b><\/a><\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0650-mil-control-circuitopen\/\" style=\"color:#0563C1;text-decoration:none;display:block;cursor:pointer\"><b>P0650<\/b><\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0650-mil-control-circuitopen\/\" style=\"color:#1a2b49;text-decoration:none;display:block;cursor:pointer\">Module-internal fault<\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0650-mil-control-circuitopen\/\" style=\"color:#0563C1\"><b><u>Full P0650 guide &rarr;<\/u><\/b><\/a><\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0651-sensor-reference-voltage-b-circuitopen\/\" style=\"color:#0563C1;text-decoration:none;display:block;cursor:pointer\"><b>P0651<\/b><\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0651-sensor-reference-voltage-b-circuitopen\/\" style=\"color:#1a2b49;text-decoration:none;display:block;cursor:pointer\">Module-internal fault<\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0651-sensor-reference-voltage-b-circuitopen\/\" style=\"color:#0563C1\"><b><u>Full P0651 guide &rarr;<\/u><\/b><\/a><\/td>\n<\/tr>\n<\/table>\n<\/div>\n<div class=\"info-section\">\n<h2>Factory Service Bulletins Worth Knowing<\/h2>\n<p>Factory service bulletins relevant to the 2003 Chevrolet Blazer 4.3L PCM\/ECM include bulletin #04-07-30-029 (June 30, 2004). This bulletin addresses a Service Engine Soon light, diagnostic trouble code P0706, an incorrect gear range indicator, and a no-start condition. The remedy is to reprogram the Powertrain Control Module. Bulletin #02-06-04-057E (March 2, 2006) covers labor operation assignments for all control module reprogramming. Bulletin #07-00-89-043 (August 23, 2007) discusses warranty administration regarding the use of parts and components, including control module calibrations, not issued through General Motors.<\/p>\n<table style=\"width:100%;border-collapse:collapse;margin:18px 0;font-size:15px\">\n<tr>\n<th style=\"border:1px solid #d6dbe3;background:#f2f5f9;padding:9px 12px;text-align:left\">Bulletin<\/th>\n<th style=\"border:1px solid #d6dbe3;background:#f2f5f9;padding:9px 12px;text-align:left\">Subject<\/th>\n<th style=\"border:1px solid #d6dbe3;background:#f2f5f9;padding:9px 12px;text-align:left\">What It Addresses<\/th>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><b>04-07-30-029<\/b><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Service Engine Soon (SES) Light On, Diagnostic Trouble Code (DTC) P0706, Gear Range Indicator I<\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Some customers may comment that the SES light is on. Some may comment that the vehicle will not start. Others may comment that the gear range indicator always\u2026<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><b>02-06-04-057<\/b><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Warranty Admin. &#8211; Labor Operation Assignments for All Control Module Reprogramming &#8211; (Mar 2, 20<\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">&mdash;<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><b>07-00-89-043<\/b><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Warranty Admin. &#8211; Use of Parts and Components (Including Control Module Calibrations) Not Issue<\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">&mdash;<\/td>\n<\/tr>\n<\/table>\n<\/div>\n<div class=\"info-section\">\n<h2>Protecting the PCM in Your 2003 Chevrolet Blazer<\/h2>\n<ul style=\"margin:14px 0 6px 0;padding-left:26px\">\n<li style=\"margin:10px 0;line-height:1.65\">Keep the battery and charging system in good condition; voltage spikes can damage the PCM.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\">Ensure all ground connections and PCM connectors are clean and tight to prevent intermittent faults.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\">Avoid jump-starting the vehicle with incorrect polarity or using a fast charger on the battery while connected.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\">Address diagnostic trouble codes promptly; ignoring them can lead to further module stress.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\">Inspect the PCM connector seals for damage or moisture intrusion, especially in wet climates.<\/li>\n<\/ul>\n<\/div>\n<div class=\"info-section\">\n<h2>Frequently Asked Questions<\/h2>\n<h3>How do I know if the PCM in my 2003 Chevrolet Blazer 4.3L is bad?<\/h3>\n<p>Common signs include a no-start condition, stalling, erratic shifting, or the gear range indicator reading incorrectly. You may also see diagnostic trouble codes like P0601 or P0706. A scan tool that cannot communicate with the module is another strong indicator.<\/p>\n<h3>Can I replace the PCM in my 2003 Blazer myself?<\/h3>\n<p>Yes, replacement is straightforward if you have basic mechanical skills. The module is located either under the hood or under the instrument panel. Factory labor time is 1.0 or 1.8 hours depending on location. Be sure to turn the ignition off before disconnecting connectors to avoid damage.<\/p>\n<h3>Do I need to program a new PCM for my 2003 Chevrolet Blazer?<\/h3>\n<p>Factory procedure requires a 0.5-hour relearn using a scan tool. However, if you purchase a VIN-programmed unit from Flagship One, the programming is already done. You can install it and drive without a dealer visit.<\/p>\n<\/div>\n<div class=\"info-section\">\n<p>When your 2003 Chevrolet Blazer 4.3L needs a PCM or ECM, you have options. You can attempt a repair if the issue is minor, but internal failures typically require replacement. A refurbished or new module from Flagship One comes pre-programmed with your VIN, saving you the time and cost of a dealer relearn. This is especially valuable given the 0.5-hour relearn time required by the factory procedure.<\/p>\n<figure style=\"margin:22px auto;text-align:center;max-width:720px\"><img decoding=\"async\" style=\"max-width:100%;height:auto;border:1px solid #e2e6ec;border-radius:8px\" src=\"https:\/\/www.fs1inc.com\/media\/wysiwyg\/googleshop\/gmtypeA\/gm-pcm-typea-1.jpg\" alt=\"Refurbished VIN-programmed PCM for the 2003 Chevrolet Blazer\" loading=\"lazy\"\/><figcaption style=\"font-size:13px;color:#667085;margin-top:8px\">A refurbished, VIN-programmed replacement PCM for the 2003 Chevrolet Blazer from Flagship One.<\/figcaption><\/figure>\n<p>Flagship One stocks a <a href=\"https:\/\/www.fs1inc.com\/2003-chevrolet-blazer-4-3l-engine-computer-pcm-ecm-ecu-programmed-plug-play.html\"><b>refurbished, VIN-programmed PCM for the 2003 Chevrolet Blazer<\/b><\/a> with a lifetime warranty, free shipping and no core charge. The full <a href=\"https:\/\/www.fs1inc.com\/gm\/chevrolet-pcm-ecm-ecu-engine-computer\/blazer-engine-computers.html\">Chevrolet Blazer module lineup<\/a> covers other engine configurations as well.<\/p>\n<\/div>\n<div class=\"info-section\">\n<h2>Final Thoughts<\/h2>\n<p>The PCM\/ECM in your 2003 Chevrolet Blazer 4.3L is a critical component for engine and transmission control. Recognizing symptoms like no-start, stalling, or incorrect gear indication can lead you to the right diagnosis. Replacement is manageable with the correct labor times and factory cautions in mind. Choosing a VIN-programmed unit simplifies the process and gets your Blazer back on the road quickly.<\/p>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Learn about the 2003 Chevrolet Blazer 4.3L PCM\/ECM: symptoms of failure, replacement labor times, factory cautions, and how VIN-programmed units simplify the job.<\/p>\n","protected":false},"author":1,"featured_media":525364,"comment_status":"open","ping_status":"closed","sticky":false,"template":"elementor_header_footer","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[258,274],"tags":[388,691,67],"class_list":["post-524292","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-car","category-chevrolet","tag-388","tag-blazer","tag-chevrolet"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.0 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>2003 Chevrolet Blazer PCM and ECM Guide: Replacement and Programming - Flagship One Blog<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.fs1inc.com\/blog\/2003-chevrolet-blazer-pcm-replacement-guide\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"2003 Chevrolet Blazer PCM and ECM Guide: Replacement and Programming - Flagship One Blog\" \/>\n<meta property=\"og:description\" content=\"Learn about the 2003 Chevrolet Blazer 4.3L PCM\/ECM: symptoms of failure, replacement labor times, factory cautions, and how VIN-programmed units simplify the job.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.fs1inc.com\/blog\/2003-chevrolet-blazer-pcm-replacement-guide\/\" \/>\n<meta property=\"og:site_name\" content=\"Flagship One Blog\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/flagshipone\" \/>\n<meta property=\"article:author\" content=\"https:\/\/www.facebook.com\/flagshipone\/\" \/>\n<meta property=\"article:published_time\" content=\"2026-07-16T06:19:23+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2026-07-19T15:11:43+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.fs1inc.com\/blog\/wp-content\/uploads\/2026\/07\/2003-chevrolet-blazer-pcm-service-figure.webp\" \/>\n\t<meta property=\"og:image:width\" content=\"612\" \/>\n\t<meta property=\"og:image:height\" content=\"611\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/webp\" \/>\n<meta name=\"author\" content=\"FlagshipOne\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:creator\" content=\"@theflagshipone\" \/>\n<meta name=\"twitter:site\" content=\"@theflagshipone\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"FlagshipOne\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"8 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/2003-chevrolet-blazer-pcm-replacement-guide\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/2003-chevrolet-blazer-pcm-replacement-guide\\\/\"},\"author\":{\"name\":\"FlagshipOne\",\"@id\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/#\\\/schema\\\/person\\\/a3cf463514bd03eb7656953ef8f75700\"},\"headline\":\"2003 Chevrolet Blazer PCM and ECM Guide: Replacement and Programming\",\"datePublished\":\"2026-07-16T06:19:23+00:00\",\"dateModified\":\"2026-07-19T15:11:43+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/2003-chevrolet-blazer-pcm-replacement-guide\\\/\"},\"wordCount\":1637,\"commentCount\":0,\"publisher\":{\"@id\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/#organization\"},\"image\":{\"@id\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/2003-chevrolet-blazer-pcm-replacement-guide\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/wp-content\\\/uploads\\\/2026\\\/07\\\/2003-chevrolet-blazer-pcm-service-figure.webp\",\"keywords\":[\"2003\",\"Blazer\",\"Chevrolet\"],\"articleSection\":[\"Car\",\"Chevrolet\"],\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/2003-chevrolet-blazer-pcm-replacement-guide\\\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/2003-chevrolet-blazer-pcm-replacement-guide\\\/\",\"url\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/2003-chevrolet-blazer-pcm-replacement-guide\\\/\",\"name\":\"2003 Chevrolet Blazer PCM and ECM Guide: Replacement and Programming - Flagship One Blog\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/2003-chevrolet-blazer-pcm-replacement-guide\\\/#primaryimage\"},\"image\":{\"@id\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/2003-chevrolet-blazer-pcm-replacement-guide\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/wp-content\\\/uploads\\\/2026\\\/07\\\/2003-chevrolet-blazer-pcm-service-figure.webp\",\"datePublished\":\"2026-07-16T06:19:23+00:00\",\"dateModified\":\"2026-07-19T15:11:43+00:00\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/2003-chevrolet-blazer-pcm-replacement-guide\\\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/2003-chevrolet-blazer-pcm-replacement-guide\\\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/2003-chevrolet-blazer-pcm-replacement-guide\\\/#primaryimage\",\"url\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/wp-content\\\/uploads\\\/2026\\\/07\\\/2003-chevrolet-blazer-pcm-service-figure.webp\",\"contentUrl\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/wp-content\\\/uploads\\\/2026\\\/07\\\/2003-chevrolet-blazer-pcm-service-figure.webp\",\"width\":612,\"height\":611,\"caption\":\"Figure from the factory control-module removal procedure for the 2003 Chevrolet Blazer\"},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/2003-chevrolet-blazer-pcm-replacement-guide\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"2003 Chevrolet Blazer PCM and ECM Guide: Replacement and Programming\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/#website\",\"url\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/\",\"name\":\"Flagship One Blog\",\"description\":\"Flagship One Inc. OEM Engine Computers  Control Modules\",\"publisher\":{\"@id\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Organization\",\"@id\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/#organization\",\"name\":\"Flagship One, Inc.\",\"url\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/#\\\/schema\\\/logo\\\/image\\\/\",\"url\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/wp-content\\\/uploads\\\/2019\\\/06\\\/web-lg-fs1-logo.png\",\"contentUrl\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/wp-content\\\/uploads\\\/2019\\\/06\\\/web-lg-fs1-logo.png\",\"width\":1341,\"height\":1098,\"caption\":\"Flagship One, Inc.\"},\"image\":{\"@id\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/#\\\/schema\\\/logo\\\/image\\\/\"},\"sameAs\":[\"https:\\\/\\\/www.facebook.com\\\/flagshipone\",\"https:\\\/\\\/x.com\\\/theflagshipone\",\"https:\\\/\\\/www.instagram.com\\\/flagship_one\",\"https:\\\/\\\/www.youtube.com\\\/channel\\\/UC0oyKphffBM2qkJ-gKPmMXw\"]},{\"@type\":\"Person\",\"@id\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/#\\\/schema\\\/person\\\/a3cf463514bd03eb7656953ef8f75700\",\"name\":\"FlagshipOne\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/351b81e51993825aea73280c48061a7205fdd2189730ebbdee5d63894c5cebb4?s=96&d=mm&r=g\",\"url\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/351b81e51993825aea73280c48061a7205fdd2189730ebbdee5d63894c5cebb4?s=96&d=mm&r=g\",\"contentUrl\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/351b81e51993825aea73280c48061a7205fdd2189730ebbdee5d63894c5cebb4?s=96&d=mm&r=g\",\"caption\":\"FlagshipOne\"},\"description\":\"The world's top supplier of programmed OEM (Original Equipment Manufacturer) Powertrain Control Modules (PCM), Engine Control Modules (ECM), Injection Control Modules (IDM), Body Control Modules (BCM), Transmission Control Modules (TCM), Engine Control Units and all other car control units. With over a decade in the business, we are the most reliable source when it comes to programming services for replacement engine control modules.\",\"sameAs\":[\"https:\\\/\\\/www.fs1inc.com\\\/\",\"https:\\\/\\\/www.facebook.com\\\/flagshipone\\\/\",\"https:\\\/\\\/www.instagram.com\\\/flagship_one\\\/\",\"https:\\\/\\\/www.linkedin.com\\\/company\\\/fs1inc\"],\"url\":\"https:\\\/\\\/www.fs1inc.com\\\/blog\\\/author\\\/flagship1inc\\\/\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"2003 Chevrolet Blazer PCM and ECM Guide: Replacement and Programming - Flagship One Blog","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.fs1inc.com\/blog\/2003-chevrolet-blazer-pcm-replacement-guide\/","og_locale":"en_US","og_type":"article","og_title":"2003 Chevrolet Blazer PCM and ECM Guide: Replacement and Programming - Flagship One Blog","og_description":"Learn about the 2003 Chevrolet Blazer 4.3L PCM\/ECM: symptoms of failure, replacement labor times, factory cautions, and how VIN-programmed units simplify the job.","og_url":"https:\/\/www.fs1inc.com\/blog\/2003-chevrolet-blazer-pcm-replacement-guide\/","og_site_name":"Flagship One Blog","article_publisher":"https:\/\/www.facebook.com\/flagshipone","article_author":"https:\/\/www.facebook.com\/flagshipone\/","article_published_time":"2026-07-16T06:19:23+00:00","article_modified_time":"2026-07-19T15:11:43+00:00","og_image":[{"width":612,"height":611,"url":"https:\/\/www.fs1inc.com\/blog\/wp-content\/uploads\/2026\/07\/2003-chevrolet-blazer-pcm-service-figure.webp","type":"image\/webp"}],"author":"FlagshipOne","twitter_card":"summary_large_image","twitter_creator":"@theflagshipone","twitter_site":"@theflagshipone","twitter_misc":{"Written by":"FlagshipOne","Est. reading time":"8 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.fs1inc.com\/blog\/2003-chevrolet-blazer-pcm-replacement-guide\/#article","isPartOf":{"@id":"https:\/\/www.fs1inc.com\/blog\/2003-chevrolet-blazer-pcm-replacement-guide\/"},"author":{"name":"FlagshipOne","@id":"https:\/\/www.fs1inc.com\/blog\/#\/schema\/person\/a3cf463514bd03eb7656953ef8f75700"},"headline":"2003 Chevrolet Blazer PCM and ECM Guide: Replacement and Programming","datePublished":"2026-07-16T06:19:23+00:00","dateModified":"2026-07-19T15:11:43+00:00","mainEntityOfPage":{"@id":"https:\/\/www.fs1inc.com\/blog\/2003-chevrolet-blazer-pcm-replacement-guide\/"},"wordCount":1637,"commentCount":0,"publisher":{"@id":"https:\/\/www.fs1inc.com\/blog\/#organization"},"image":{"@id":"https:\/\/www.fs1inc.com\/blog\/2003-chevrolet-blazer-pcm-replacement-guide\/#primaryimage"},"thumbnailUrl":"https:\/\/www.fs1inc.com\/blog\/wp-content\/uploads\/2026\/07\/2003-chevrolet-blazer-pcm-service-figure.webp","keywords":["2003","Blazer","Chevrolet"],"articleSection":["Car","Chevrolet"],"inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/www.fs1inc.com\/blog\/2003-chevrolet-blazer-pcm-replacement-guide\/#respond"]}]},{"@type":"WebPage","@id":"https:\/\/www.fs1inc.com\/blog\/2003-chevrolet-blazer-pcm-replacement-guide\/","url":"https:\/\/www.fs1inc.com\/blog\/2003-chevrolet-blazer-pcm-replacement-guide\/","name":"2003 Chevrolet Blazer PCM and ECM Guide: Replacement and Programming - Flagship One Blog","isPartOf":{"@id":"https:\/\/www.fs1inc.com\/blog\/#website"},"primaryImageOfPage":{"@id":"https:\/\/www.fs1inc.com\/blog\/2003-chevrolet-blazer-pcm-replacement-guide\/#primaryimage"},"image":{"@id":"https:\/\/www.fs1inc.com\/blog\/2003-chevrolet-blazer-pcm-replacement-guide\/#primaryimage"},"thumbnailUrl":"https:\/\/www.fs1inc.com\/blog\/wp-content\/uploads\/2026\/07\/2003-chevrolet-blazer-pcm-service-figure.webp","datePublished":"2026-07-16T06:19:23+00:00","dateModified":"2026-07-19T15:11:43+00:00","breadcrumb":{"@id":"https:\/\/www.fs1inc.com\/blog\/2003-chevrolet-blazer-pcm-replacement-guide\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.fs1inc.com\/blog\/2003-chevrolet-blazer-pcm-replacement-guide\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/www.fs1inc.com\/blog\/2003-chevrolet-blazer-pcm-replacement-guide\/#primaryimage","url":"https:\/\/www.fs1inc.com\/blog\/wp-content\/uploads\/2026\/07\/2003-chevrolet-blazer-pcm-service-figure.webp","contentUrl":"https:\/\/www.fs1inc.com\/blog\/wp-content\/uploads\/2026\/07\/2003-chevrolet-blazer-pcm-service-figure.webp","width":612,"height":611,"caption":"Figure from the factory control-module removal procedure for the 2003 Chevrolet Blazer"},{"@type":"BreadcrumbList","@id":"https:\/\/www.fs1inc.com\/blog\/2003-chevrolet-blazer-pcm-replacement-guide\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/www.fs1inc.com\/blog\/"},{"@type":"ListItem","position":2,"name":"2003 Chevrolet Blazer PCM and ECM Guide: Replacement and Programming"}]},{"@type":"WebSite","@id":"https:\/\/www.fs1inc.com\/blog\/#website","url":"https:\/\/www.fs1inc.com\/blog\/","name":"Flagship One Blog","description":"Flagship One Inc. OEM Engine Computers  Control Modules","publisher":{"@id":"https:\/\/www.fs1inc.com\/blog\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.fs1inc.com\/blog\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Organization","@id":"https:\/\/www.fs1inc.com\/blog\/#organization","name":"Flagship One, Inc.","url":"https:\/\/www.fs1inc.com\/blog\/","logo":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/www.fs1inc.com\/blog\/#\/schema\/logo\/image\/","url":"https:\/\/www.fs1inc.com\/blog\/wp-content\/uploads\/2019\/06\/web-lg-fs1-logo.png","contentUrl":"https:\/\/www.fs1inc.com\/blog\/wp-content\/uploads\/2019\/06\/web-lg-fs1-logo.png","width":1341,"height":1098,"caption":"Flagship One, Inc."},"image":{"@id":"https:\/\/www.fs1inc.com\/blog\/#\/schema\/logo\/image\/"},"sameAs":["https:\/\/www.facebook.com\/flagshipone","https:\/\/x.com\/theflagshipone","https:\/\/www.instagram.com\/flagship_one","https:\/\/www.youtube.com\/channel\/UC0oyKphffBM2qkJ-gKPmMXw"]},{"@type":"Person","@id":"https:\/\/www.fs1inc.com\/blog\/#\/schema\/person\/a3cf463514bd03eb7656953ef8f75700","name":"FlagshipOne","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/secure.gravatar.com\/avatar\/351b81e51993825aea73280c48061a7205fdd2189730ebbdee5d63894c5cebb4?s=96&d=mm&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/351b81e51993825aea73280c48061a7205fdd2189730ebbdee5d63894c5cebb4?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/351b81e51993825aea73280c48061a7205fdd2189730ebbdee5d63894c5cebb4?s=96&d=mm&r=g","caption":"FlagshipOne"},"description":"The world's top supplier of programmed OEM (Original Equipment Manufacturer) Powertrain Control Modules (PCM), Engine Control Modules (ECM), Injection Control Modules (IDM), Body Control Modules (BCM), Transmission Control Modules (TCM), Engine Control Units and all other car control units. With over a decade in the business, we are the most reliable source when it comes to programming services for replacement engine control modules.","sameAs":["https:\/\/www.fs1inc.com\/","https:\/\/www.facebook.com\/flagshipone\/","https:\/\/www.instagram.com\/flagship_one\/","https:\/\/www.linkedin.com\/company\/fs1inc"],"url":"https:\/\/www.fs1inc.com\/blog\/author\/flagship1inc\/"}]}},"_links":{"self":[{"href":"https:\/\/www.fs1inc.com\/blog\/wp-json\/wp\/v2\/posts\/524292","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.fs1inc.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fs1inc.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fs1inc.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fs1inc.com\/blog\/wp-json\/wp\/v2\/comments?post=524292"}],"version-history":[{"count":3,"href":"https:\/\/www.fs1inc.com\/blog\/wp-json\/wp\/v2\/posts\/524292\/revisions"}],"predecessor-version":[{"id":537805,"href":"https:\/\/www.fs1inc.com\/blog\/wp-json\/wp\/v2\/posts\/524292\/revisions\/537805"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.fs1inc.com\/blog\/wp-json\/wp\/v2\/media\/525364"}],"wp:attachment":[{"href":"https:\/\/www.fs1inc.com\/blog\/wp-json\/wp\/v2\/media?parent=524292"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fs1inc.com\/blog\/wp-json\/wp\/v2\/categories?post=524292"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fs1inc.com\/blog\/wp-json\/wp\/v2\/tags?post=524292"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}