1999 Chrysler 300M PCM Replacement & Relearn Guide for Owners
The Powertrain Control Module (PCM) in your 1999 Chrysler 300M manages engine and transmission functions. Failure may cause poor performance, stalling, or communication errors with diagnostic tools.
Quick Summary
- PCM controls engine and transmission operations in the 1999 Chrysler 300M.
- Replacement typically requires 0.4 hours of labor for removal and installation.
- A relearn procedure of 0.5 hours is needed after installation.
- Factory programming requires VIN and mileage input via the DRB scan tool.
- Common symptoms include no-start conditions, stalling, or erratic shifting.
If your 1999 Chrysler 300M is experiencing unexplained stalling, rough idling, or a no-start condition, the Powertrain Control Module (PCM) may be at fault. This critical component oversees engine and transmission performance, ensuring smooth operation. Replacing it involves more than just swapping parts—proper programming and relearning are essential to restore functionality. Understanding the process helps you make informed decisions, whether you’re tackling the job yourself or working with a mechanic. This guide covers what the PCM does, where it’s located, and what to expect during replacement and programming.
What the PCM Does in a 1999 Chrysler 300M
The Powertrain Control Module (PCM) in your 1999 Chrysler 300M acts as the brain for both engine and transmission systems. It processes data from sensors to optimize fuel delivery, ignition timing, and shift points, ensuring efficient performance. When the PCM fails, you may notice poor drivability, such as hesitation or sudden stalling. Replacement involves installing a new unit, which must be programmed with your vehicle’s specific data. For this model, replacement engine computers for the 300M are designed to integrate seamlessly with the existing systems, but proper initialization is key to avoiding further issues.
Where the PCM Is Located and What Replacement Involves
In the 1999 Chrysler 300M, the PCM is typically mounted in the engine bay, often near the firewall or strut tower. Replacing it involves disconnecting the battery, removing the module’s electrical connectors, and unbolting the unit. The labor time for removal and reinstallation is usually 0.4 hours. Once the new module is in place, reconnecting the battery and securing all fasteners completes the physical installation. Access may require moving other components, but no specialized tools are typically needed beyond basic hand tools.
How to Reach the PCM on the 1999 Chrysler 300M
- Remove speed control servo and bracket and reposition out of the way ei.
- Remove washer bottle filler neck.
- Remove Transmission Control Module (TCM) reposition out of the way.
- Remove PCM Disconnect PCM 2 40-way connector.
Work with the ignition off, and treat the module as static-sensitive: avoid touching the connector pins at any point.
| Operation | Configuration | Book Time |
|---|---|---|
| Powertrain Control Module Relearn | All configurations | 0.5 hr |
| Powertrain Control Module R&R | All configurations | 0.4 hr |
| Engine Control Module Relearn | All configurations | 0.5 hr |
| Engine Control Module R&R | All configurations | 0.4 hr |
Programming Requirements After Replacement
After installing a new PCM in your 1999 Chrysler 300M, the factory procedure requires reprogramming the module with the vehicle’s original VIN and mileage using the DRB scan tool. This step ensures the module communicates correctly with the engine and transmission. Additionally, you’ll need to reconnect the speed control servo and bracket, then tighten all fasteners. The radio and clock must also be reset. However, if you opt for a VIN-programmed replacement unit, these steps are already completed, saving you time and reducing the risk of errors during setup.
Symptoms of a Failing PCM
A failing PCM in your 1999 Chrysler 300M may cause a range of symptoms, including intermittent stalling, rough idling, or a no-start condition. You might also notice erratic shifting or poor acceleration, as the module struggles to manage transmission and engine functions. Diagnostic trouble codes like internal control module memory checksum error often appear, indicating corruption within the PCM’s memory. If your scan tool fails to communicate with the module, that’s another sign of potential failure. Addressing these issues promptly can prevent further drivability problems.
Module Trouble Codes on the 1999 Chrysler 300M
The 1999 Chrysler 300M may log specific trouble codes when the PCM begins to fail. These codes help pinpoint issues within the module’s internal circuits or memory. Below are the documented codes associated with PCM problems in this vehicle.
| Code | Meaning | Full Guide |
|---|---|---|
| P0600 | Module-internal fault | Full P0600 guide → |
| P0601 | Internal memory checksum error | Full P0601 guide → |
| P0622 | Module-internal fault | Full P0622 guide → |
| P0645 | Module-internal fault | Full P0645 guide → |
| P1682 | Module-internal fault | Full P1682 guide → |
| P1683 | Control module fault | Full P1683 guide → |
| P1685 | Module-internal fault | — |
| P1686 | Module-internal fault | — |
| P1687 | Module-internal fault | — |
| P1695 | Module-internal fault | — |
| P1696 | Module-internal fault | — |
| P1697 | Module-internal fault | — |
Factory Service Bulletins Worth Knowing
Chrysler issued service bulletin #08-030-06 Rev. A to address Powertrain Control Module initialization procedures for this model. The bulletin outlines steps to ensure proper communication between the PCM and other vehicle systems after replacement. Following these guidelines helps prevent issues like stalling or poor performance, which may arise if the module isn’t correctly initialized.
| Bulletin | Subject | What It Addresses |
|---|---|---|
| 08-030-06 Rev. A | 08-030-06 Rev. A Powertrain Control Module Initialization | — |
Protecting the PCM in Your 1999 Chrysler 300M
- Keep your vehicle’s charging system in good condition to avoid voltage spikes that may damage the PCM.
- Ensure all electrical connectors are clean and securely fastened to prevent corrosion or poor contact.
- Avoid jump-starting the battery with excessive voltage, as this can harm sensitive electronics.
- Address any diagnostic trouble codes promptly to prevent cascading failures.
- Inspect the PCM’s connector seals regularly to keep moisture out and maintain a secure connection.
Frequently Asked Questions
Why does my 1999 Chrysler 300M stall after replacing the PCM?
Stalling after PCM replacement often occurs if the module isn’t properly initialized or programmed with the vehicle’s VIN and mileage. A relearn procedure using the DRB scan tool is typically required to restore normal operation.
Can I drive my 1999 Chrysler 300M with a bad PCM?
Driving with a faulty PCM may lead to poor performance, stalling, or even a no-start condition. It’s best to address the issue promptly to avoid further complications or potential safety risks.
How do I know if my 1999 Chrysler 300M PCM needs replacement?
Common signs include diagnostic trouble codes like P0601, erratic shifting, stalling, or a no-start condition. If your scan tool can’t communicate with the PCM, that’s another strong indicator of failure.
If your 1999 Chrysler 300M is showing signs of PCM failure, you have options. A repair may be possible, but replacement is often more reliable. Opting for a pre-programmed module can simplify the process, ensuring your vehicle is back on the road with minimal downtime. Consider the labor and programming requirements when deciding the best approach for your situation.
Flagship One stocks a refurbished, VIN-programmed PCM for the 1999 Chrysler 300M with a lifetime warranty, free shipping and no core charge. The full Chrysler 300M module lineup covers other engine configurations as well.
Final Thoughts
The 1999 Chrysler 300M relies on its PCM to manage critical engine and transmission functions. If you’re experiencing symptoms like stalling or poor performance, addressing the issue promptly can restore smooth operation. Whether you choose to replace the module yourself or seek professional help, understanding the process ensures a successful outcome.