{"id":534626,"date":"2026-07-17T17:52:04","date_gmt":"2026-07-17T21:52:04","guid":{"rendered":"https:\/\/www.fs1inc.com\/blog\/?p=534626"},"modified":"2026-07-19T12:23:26","modified_gmt":"2026-07-19T16:23:26","slug":"1999-pontiac-grand-prix-pcm-replacement-guide","status":"publish","type":"post","link":"https:\/\/www.fs1inc.com\/blog\/1999-pontiac-grand-prix-pcm-replacement-guide\/","title":{"rendered":"1999 Pontiac Grand Prix 3.1L PCM Replacement &#038; Programming Guide"},"content":{"rendered":"<div class=\"container\">\n<section class=\"hero\">\n<div class=\"code-badge\">PCM<\/div>\n<h1>1999 Pontiac Grand Prix 3.1L PCM Replacement &amp; Programming Guide<\/h1>\n<p class=\"hero-subtitle\">The Powertrain Control Module (PCM) in the 1999 Pontiac Grand Prix 3.1L manages engine fuel, ignition, and transmission shift points. Failure often causes no-start, stalling, or poor drivability. The module must be programmed with the remaining engine oil life to prevent a default 100% reading.<\/p>\n<\/section>\n<div class=\"quick-summary\">\n<h2>Quick Summary<\/h2>\n<ul>\n<li>The PCM is located next to the air cleaner assembly; factory book time for removal and replacement is 0.9 hours.<\/li>\n<li>A PCM relearn procedure takes 0.5 hours and is required after installation to synchronize the module with the vehicle.<\/li>\n<li>Factory cautions stress that the ignition must be OFF when connecting or disconnecting PCM connectors to avoid internal damage.<\/li>\n<li>Before replacement, record the remaining engine oil life; if the new module is not programmed with that value, oil life defaults to 100%.<\/li>\n<li>Three service bulletins address PCM reprogramming, connector service kits, and labor operation assignments for reprogramming.<\/li>\n<\/ul>\n<\/div>\n<div class=\"info-section\">\n<p>If your 1999 Pontiac Grand Prix 3.1L is experiencing intermittent stalling, a no-start condition, or a persistent check engine light, the Powertrain Control Module (PCM) may be at fault. The PCM is the central computer that controls engine and transmission functions. This guide explains what the PCM does in your Grand Prix, where it is located, how replacement is performed, and what factory procedures are necessary after installation. You will also learn about common failure symptoms, related trouble codes, and factory service bulletins that apply to this model. Understanding these details helps you make an informed decision about repair or replacement.<\/p>\n<\/div>\n<div class=\"info-section\">\n<h2>What the PCM Does in a 1999 Pontiac Grand Prix<\/h2>\n<p>The Powertrain Control Module in the 1999 Pontiac Grand Prix 3.1L is the vehicle&#8217;s primary engine computer. It receives signals from sensors throughout the engine and transmission, then adjusts fuel delivery, ignition timing, and shift patterns to optimize performance and emissions. The PCM also monitors system health and stores diagnostic trouble codes when faults occur. Because it controls so many critical functions, a failing PCM can cause a wide range of drivability issues. When the original unit fails, a <a href=\"https:\/\/www.fs1inc.com\/gm\/pontiac-pcm-ecm-ecu-engine-computer\/grand-prix-engine-computers.html\">replacement PCMs for the Grand Prix<\/a> must be properly programmed to match the vehicle&#8217;s VIN and options, including the remaining engine oil life, to restore full functionality.<\/p>\n<\/div>\n<div class=\"info-section\">\n<h2>Where the PCM Is Located and What Replacement Involves<\/h2>\n<p>The PCM on the 1999 Pontiac Grand Prix 3.1L is located next to the air cleaner assembly, according to the factory removal procedure. Access typically involves removing the air cleaner housing or ductwork to reach the module. The factory book time for PCM removal and replacement is 0.9 hours, and an additional 0.5 hours is allowed for the PCM relearn procedure. A critical factory caution states that the ignition must be OFF when disconnecting or reconnecting the PCM connectors to prevent internal damage. Also, before replacement, you should record the remaining engine oil life; if the new module is not programmed with that value, the oil life indicator will default to 100%.<\/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\/1999-pontiac-grand-prix-ecm-location-card.webp\" alt=\"1999 Pontiac Grand Prix PCM location diagram\" loading=\"lazy\"\/><figcaption style=\"font-size:13px;color:#667085;margin-top:8px\">Typical PCM mounting area on the 1999 Pontiac Grand Prix (reference).<\/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 1999 Pontiac Grand Prix<\/h3>\n<ol style=\"margin:14px 0 6px 0;padding-left:26px\">\n<li style=\"margin:10px 0;line-height:1.65\"><b>Disconnect<\/b> the negative battery.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\"><b>Disconnect<\/b> the IAT sensor electrical connector.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\"><b>Remove<\/b> the 3 bolts from the inner fender brace and.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\"><b>Remove<\/b> the brace.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\"><b>Loosen<\/b> the clamps securing the air intake duct\/MAF sensor to.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\"><b>Remove<\/b> the air intake duct\/MAF sensor from the.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\"><b>Remove<\/b> the 2 screws from the 2 air.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\"><b>Remove<\/b> the air cleaner housing cover assembly.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\"><b>Disconnect<\/b> the PCM connectors.<\/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\">Engine Control Module R&amp;R<\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">All configurations<\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">0.9 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<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\">Powertrain Control Module R&amp;R<\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">One<\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">0.9 hr<\/td>\n<\/tr>\n<\/table>\n<\/div>\n<div class=\"info-section\">\n<h2>Programming Requirements After Replacement<\/h2>\n<p>After installing a new PCM in the 1999 Pontiac Grand Prix 3.1L, the factory procedure requires EEPROM reprogramming and setting the remaining engine oil life. The service manual notes that PCM service normally consists of either replacement or reprogramming. Choosing <a href=\"https:\/\/www.fs1inc.com\/1999-pontiac-grand-prix-3-1l-engine-computer-pcm-ecm-ecu-programmed-plug-play.html\">a VIN-programmed replacement unit<\/a> from Flagship One means the module arrives already programmed with your vehicle&#8217;s VIN and calibration data, so the post-install programming steps are already completed. This eliminates the need for a separate reprogramming session and ensures the oil life value can be set correctly during the relearn process.<\/p>\n<\/div>\n<div class=\"info-section\">\n<h2>Symptoms of a Failing PCM<\/h2>\n<p>A failing PCM in the 1999 Pontiac Grand Prix 3.1L may cause a no-start condition, intermittent stalling, rough idle, misfire codes, or transmission shifting problems. The check engine light often illuminates, and a scan tool may fail to communicate with the module. One common internal fault is <a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0601-internal-control-module-memory-checksum-error\/\">internal control module error<\/a>, which indicates a memory or checksum failure within the PCM. Other symptoms include poor fuel economy, hesitation during acceleration, and erratic gauge readings. Because the PCM controls so many systems, these issues can mimic other component failures, making diagnosis important.<\/p>\n<\/div>\n<div class=\"info-section\">\n<h2>Module Trouble Codes on the 1999 Pontiac Grand Prix<\/h2>\n<p>The following trouble codes are documented as module-internal faults for the 1999 Pontiac Grand Prix 3.1L PCM. These codes indicate problems within the control module itself rather than external sensors or circuits.<\/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-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-p0656-fuel-level-output-circuit\/\" style=\"color:#0563C1;text-decoration:none;display:block;cursor:pointer\"><b>P0656<\/b><\/a><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><a href=\"https:\/\/www.fs1inc.com\/blog\/dtc-p0656-fuel-level-output-circuit\/\" 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-p0656-fuel-level-output-circuit\/\" style=\"color:#0563C1\"><b><u>Full P0656 guide &rarr;<\/u><\/b><\/a><\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\"><b>P1626<\/b><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Module-internal fault<\/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>P1629<\/b><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Module-internal fault<\/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>P1635<\/b><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Module-internal fault<\/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>P1637<\/b><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Module-internal fault<\/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>P1639<\/b><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Module-internal fault<\/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>P1653<\/b><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Module-internal fault<\/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>P1673<\/b><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Module-internal fault<\/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>P1689<\/b><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Module-internal fault<\/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>Factory Service Bulletins Worth Knowing<\/h2>\n<p>Three factory service bulletins apply to the 1999 Pontiac Grand Prix 3.1L PCM. Bulletin #99-06-04-053 (October 1999) provides information on PCM reprogramming. Bulletin #83-81-32 (September 1998) introduces new PCM connector service kits for repairing damaged connectors. Bulletin #02-06-04-057E (March 2006) assigns labor operation numbers for all control module reprogramming work. These bulletins may be relevant when diagnosing PCM-related issues or performing replacement.<\/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>99-06-04-053<\/b><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">Info &#8211; PCM Reprogramming &#8211; (Oct 26, 1999)<\/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>83-81-32<\/b><\/td>\n<td style=\"border:1px solid #d6dbe3;padding:9px 12px\">INFO &#8211; NEW PCM CONNECTOR SERVICE KITS &#8211; (Sep 16, 1998)<\/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>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<\/table>\n<\/div>\n<div class=\"info-section\">\n<h2>Protecting the PCM in Your 1999 Pontiac Grand Prix<\/h2>\n<ul style=\"margin:14px 0 6px 0;padding-left:26px\">\n<li style=\"margin:10px 0;line-height:1.65\">Maintain the charging system in good condition; voltage spikes from a failing alternator can damage the PCM.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\">Keep battery and chassis grounds clean and tight to ensure stable voltage to the module.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\">Avoid jump-starting the vehicle with a running donor vehicle; use a battery charger instead to prevent voltage surges.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\">Address diagnostic trouble codes promptly, especially those related to sensors or power supply, to reduce stress on the PCM.<\/li>\n<li style=\"margin:10px 0;line-height:1.65\">Inspect the PCM connector seals and wiring for corrosion or damage; replace the connector if needed using the factory service kit.<\/li>\n<\/ul>\n<\/div>\n<div class=\"info-section\">\n<p>When the PCM in your 1999 Pontiac Grand Prix 3.1L fails, you have two main options: repair the original module or replace it with a refurbished unit. Repair may be possible for some internal faults, but replacement with a pre-programmed unit often provides a more reliable solution. Flagship One offers refurbished PCMs that are VIN-programmed for your Grand Prix, eliminating the need for dealer reprogramming.<\/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 1999 Pontiac Grand Prix\" loading=\"lazy\"\/><figcaption style=\"font-size:13px;color:#667085;margin-top:8px\">A refurbished, VIN-programmed replacement PCM for the 1999 Pontiac Grand Prix from Flagship One.<\/figcaption><\/figure>\n<p>Flagship One stocks a <a href=\"https:\/\/www.fs1inc.com\/1999-pontiac-grand-prix-3-1l-engine-computer-pcm-ecm-ecu-programmed-plug-play.html\"><b>refurbished, VIN-programmed PCM for the 1999 Pontiac Grand Prix<\/b><\/a> with a lifetime warranty, free shipping and no core charge. The full <a href=\"https:\/\/www.fs1inc.com\/gm\/pontiac-pcm-ecm-ecu-engine-computer\/grand-prix-engine-computers.html\">Pontiac Grand Prix 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 1999 Pontiac Grand Prix 3.1L relies on its PCM for engine and transmission control. Recognizing symptoms like no-start or stalling, and following factory cautions during replacement, can prevent further issues. A pre-programmed replacement PCM from Flagship One simplifies the process by handling the programming before installation.<\/p>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>If your 1999 Pontiac Grand Prix 3.1L has PCM failure symptoms like no-start or check engine light, follow factory cautions to avoid damage. Learn replacement and programming.<\/p>\n","protected":false},"author":1,"featured_media":522437,"comment_status":"open","ping_status":"closed","sticky":false,"template":"elementor_header_footer","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[258,474],"tags":[52,1569,72],"class_list":["post-534626","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-car","category-pontiac","tag-52","tag-grand-prix","tag-pontiac"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.0 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>1999 Pontiac Grand Prix 3.1L PCM Replacement &amp; Programming Guide - 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\/1999-pontiac-grand-prix-pcm-replacement-guide\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"1999 Pontiac Grand Prix 3.1L PCM Replacement &amp; Programming Guide - Flagship One Blog\" \/>\n<meta property=\"og:description\" content=\"If your 1999 Pontiac Grand Prix 3.1L has PCM failure symptoms like no-start or check engine light, follow factory cautions to avoid damage. 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