Restore Peak Performance and Reliability to Your Vehicle
Is your Cadillac, Chevy, or GMC suffering from frustrating and unpredictable issues like stalling, erratic idling, a persistent check engine light, or a complete no-start condition? Before you resign yourself to a costly and time-consuming visit to the dealership, consider the heart of your vehicle’s engine management system: the Engine Control Module (ECM). As a technician with over two decades of experience, I’ve seen firsthand how a failing ECM can mimic a dozen other problems, leading to expensive and unnecessary repairs. This replacement Engine Control Module is the definitive, reliable solution to get your vehicle running smoothly again.
This isn’t just a part in a box; it’s a complete service. We take the guesswork and extra cost out of the equation by pre-programming this module specifically for your vehicle using your VIN. This ensures it arrives with the latest GM software updates, ready for a straightforward installation. By providing your VIN at checkout, you get a component that communicates flawlessly with your vehicle’s other systems, restoring the precise fuel delivery, ignition timing, and emissions control that the factory intended. For many DIYers and professional shops, this plug-and-play convenience is a game-changer.
A Technician’s Notebook: The Ghost in the Machine
I remember a 2009 Cadillac CTS-V that came into the bay with a complaint of intermittent no-start and random stalling. The owner had already replaced the battery and alternator. The scan tool showed a handful of communication loss codes (U-codes) but nothing pointing directly to a single component. After hours of chasing wires and checking grounds, we hooked up a lab scope to the ECM’s power and data lines. We noticed a voltage drop inside the module itself right before it would shut down. The ECM was failing internally, but only when it reached a certain temperature. A new, properly programmed ECM like this one solved the problem instantly. It’s a classic case where the symptoms are misleading, but the root cause is the vehicle’s central computer.
Common Signs of a Failing Engine Computer
- ✔ Check Engine Light is on with codes like P0601 (Internal Control Module Memory Check Sum Error) or P0606 (ECM/PCM Processor Fault).
- ✔ Vehicle refuses to start or starts and immediately stalls.
- ✔ Noticeable decrease in fuel economy and engine performance.
- ✔ Engine misfires, stumbles, or hesitates during acceleration.
- ✔ Automatic transmission shifts harshly or at the wrong times.
- ✔ Loss of communication with the scan tool, making diagnostics impossible.
A Straightforward Guide to Installation
- ✔ Safety First: Disconnect the negative terminal from your vehicle’s battery and wait at least 10 minutes to allow all systems to discharge.
- ✔ Locate the ECM: On the 2009 Cadillac XLR, the ECM is typically located in the right-hand front of the engine compartment. On other models, it could be on the firewall or near the air cleaner box. Consult a service manual for your specific vehicle if unsure.
- ✔ Disconnect Connectors: Carefully release the locking tabs on the electrical wiring harnesses and pull them straight out from the module. Do not force them. Inspect connectors for any corrosion or bent pins.
- ✔ Remove the Old Module: Unbolt the old ECM from its mounting bracket. Keep the hardware as you will need it for the new module.
- ✔ Install the New Module: Mount your new, pre-programmed ECM onto the bracket and secure it with the original hardware.
- ✔ Reconnect Everything: Firmly plug the wiring harnesses back into the new module until they click into place. Reconnect the negative battery terminal.
- ✔ Perform Relearn Procedure: While the module is programmed, your vehicle may require a security or crank-sensor relearn procedure. For many GM vehicles, this involves turning the key to ‘ON’ for 10-15 minutes, then ‘OFF’ for 30 seconds, and repeating this cycle three times before attempting to start the engine.
Verified Vehicle Compatibility
This module is a direct replacement for a wide range of GM vehicles and is interchangeable with service numbers 12636659, 12639300, 1263605, 12628993, 12628911, 12625453, 12630464, and 12678512. Please verify your model and engine below:
- Buick DTS: 2009-2011
- Buick Lucerne: 2009-2011 (4.6L)
- Cadillac CTS: 2009 (6.2L)
- Cadillac SRX: 2009 (4.6L)
- Cadillac STS: 2009 (4.4L, 4.6L), 2010 (4.6L)
- Cadillac XLR: 2009 (ID 12625453 or 12636659)
- Chevrolet Colorado: 2009, 2010-2012 (2.9L, 3.7L)
- Chevrolet Corvette: 2009 (ZR1)
- Chevrolet Trailblazer: 2009 (6.0L)
- GMC Canyon: 2009, 2010-2012 (2.9L, 3.7L)
- GMC Envoy: 2009 (5.3L)
- Hummer H3: 2009, 2010 (3.7L)
- Saab 9-7x: 2009
Frequently Asked Questions
Why do you need my VIN?
Your Vehicle Identification Number (VIN) allows us to program the module with the exact software and calibrations specific to your vehicle’s engine, transmission, and options. This ensures a perfect match and proper function without needing a trip to the dealer for programming.
Is this a plug-and-play part?
Yes, this ECM comes pre-programmed to your VIN. In most cases, you can install it and start the vehicle. However, some GM vehicles may require a simple, key-on/key-off security relearn procedure that you can perform yourself in about 30 minutes without any special tools.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the original ECM (e.g., codes P0601, P0606), then this part is the correct fix. It’s crucial to properly diagnose the vehicle first, as other failing sensors or wiring issues can also trigger a check engine light.
Do I need to send my old ECM back?
No core charge or return is required for this part. You can keep or responsibly recycle your old module.
What if my part number isn’t an exact match to 12622175?
This module is a direct replacement for several GM service numbers, including 12636659, 12628993, and others listed in the description. As long as your vehicle is on the compatibility list and your old part number is one of the listed interchanges, this part will work correctly.