Restore Your Vehicle’s Core Performance and Reliability
Is your Pontiac Montana, or another compatible GM vehicle, giving you headaches? Unexplained stalling, a persistent Check Engine Light, rough idling, or failing an emissions test are all classic signs that your vehicle’s ‘brain’—the Powertrain Control Module (PCM)—is failing. As a technician with over two decades of experience, I’ve seen firsthand how a faulty PCM can turn a reliable vehicle into a source of constant frustration. This isn’t just an inconvenience; it affects your vehicle’s safety, fuel economy, and overall drivability.
This isn’t just a replacement part; it’s a comprehensive solution. We offer a high-quality replacement PCM (Part No. 89017735) that comes fully programmed to your vehicle’s specific Vehicle Identification Number (VIN). This critical step ensures that the module communicates perfectly with your engine, transmission, and all related systems, right out of the box. We load the latest GM-certified software, addressing common factory bugs and optimizing performance based on years of real-world data. By providing us with your VIN at checkout, you eliminate the need for an expensive trip to the dealership for programming—a savings of both time and money.
Case Study: A Tricky Diagnosis
I remember a 2004 Chevy Impala that came into the shop with an intermittent no-start and stalling issue that no one could pin down. The owner had already replaced the fuel pump and crank sensor. After connecting my scan tool, I noticed intermittent communication loss with the PCM. Instead of throwing parts at it, we tested the power and ground circuits to the module—they were solid. The culprit was internal PCM failure, a common issue on these platforms. We installed a pre-programmed module just like this one, performed the security relearn, and the car ran perfectly. It’s a textbook example of how a reliable 2003-2005 Montana PCM or its equivalent can be the definitive fix.
Common Signs of a Failing GM PCM
If you’re experiencing any of the following, a failing PCM is a likely cause. A proper diagnosis is always recommended, but these symptoms are strong indicators for many GM vehicles from this era.
- ✔ Persistent Check Engine Light (CEL) that won’t clear.
- ✔ Diagnostic Trouble Codes (DTCs) related to internal module failure, such as P0601, P0602, or P0606.
- ✔ Random or intermittent engine stalling, especially when warm.
- ✔ Noticeable decrease in fuel efficiency.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Engine misfires or runs rough with no other apparent cause.
- ✔ Complete no-start condition where the engine cranks but won’t fire.
- ✔ Failure to communicate with a diagnostic scan tool.
A Straightforward Guide to Installation
Replacing your 2003-2005 Montana PCM is a manageable job for a confident DIYer. While the exact location varies slightly by model (check your service manual), the process is generally the same. After installation, a simple security relearn procedure is required, which does not need special tools.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post.
- Locate the PCM: On most of these vehicles, the PCM is found in the engine compartment, often on the driver’s side, sometimes inside the air filter housing.
- Disconnect Connectors: Carefully release the locking tabs and unplug the large electrical harness connectors from the old module. Inspect the connectors for any corrosion or damage.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket.
- Install the New Module: Mount your new, pre-programmed PCM and securely reconnect the electrical harnesses. You should hear a ‘click’ as they lock into place.
- Reconnect Battery: Reattach the negative battery terminal.
- Perform Security Relearn: Follow the included instructions for the GM Security Relearn Procedure (often called the ’30-minute relearn’). This syncs the new PCM with your vehicle’s anti-theft system.
- Final Check: Start the vehicle and check for a Check Engine Light and ensure it runs smoothly. Your repair is complete!
Verified Vehicle Compatibility
This module is a direct replacement for part numbers 89017735, 12583827, and 12583826. It is guaranteed to fit and function correctly in the following GM vehicles. Please match your vehicle and, where noted, the specific engine or ID number for a perfect match.
ALERO 04 (3.4L)
AZTEK 03 (ID 12583827)
AZTEK 04-05
BONNEVILLE 04-05 (3.8L)
CENTURY 03-05
GRAND AM 03 (3.4L, ID 12583827)
GRAND AM 04-05 (3.4L)
GRAND PRIX 03 (3.1L, ID 12583827)
IMPALA 03 (3.4L, ID 12583827)
IMPALA 04-05
LESABRE 04-05
MALIBU 03 (ID 12583827)
MONTE CARLO 03 (3.4L, ID 12583827)
MONTE CARLO 04-05
MONTANA 03-04
MONTANA 05 (Base)
PARK AVENUE 04 (ID 12583827)
PARK AVENUE 05
RENDEZVOUS 03-05 (ID 12583827)
SILHOUETTE 03-04
VENTURE 03 (ID 12583827)
VENTURE 04-05
Frequently Asked Questions
Frequently Asked Questions
How does the VIN programming work?
After you place your order, you will need to provide us with your 17-digit Vehicle Identification Number (VIN). We use this number to flash the module with the exact software and calibrations your specific vehicle requires from the factory, ensuring seamless integration.
Do I need any special tools to install this PCM?
No. Basic hand tools (like a socket set) are all that’s needed for the physical installation. The only other step is the Security Relearn Procedure, which is a sequence of key turns and waiting periods that you can do yourself right in your driveway.
Will this fix my specific problem?
This module is a direct solution for a failed PCM. If your vehicle has been properly diagnosed with a faulty computer (e.g., showing code P0601 or experiencing communication failures), this part will resolve those issues and the related symptoms like stalling or poor performance.
Is this a used part?
This is a quality, inspected, and tested recycled OEM part that has been verified to meet or exceed original factory specifications. We then program it with the latest software for your vehicle.
What is the warranty on this part?
We stand behind our work. This module comes with a comprehensive warranty that covers any defects in the part or the programming. Please see our warranty page for full details.