Restore Peak Performance to Your GM Vehicle
Is your Cadillac, Buick, or GMC suffering from frustrating and unpredictable engine problems? A faulty Engine Control Module (ECM) is often the culprit behind issues like a persistent Check Engine Light, rough idling, stalling, or a complete no-start condition. As the central computer for your engine, a failing ECM can disrupt everything from fuel delivery and ignition timing to transmission shifting. This isn’t just an annoyance—it’s a critical failure that compromises your vehicle’s reliability and performance.
This Engine Control Module, part number 12623325, is the definitive solution. We take the guesswork and high cost out of the repair process. Before this module ships, our technicians will program it with the latest GM-certified software updates, specifically matched to your vehicle’s VIN. This means it arrives at your door ready for a straightforward installation, eliminating the need for expensive dealership programming or specialized scan tools. Restore your vehicle’s precise engine management and get back on the road with confidence.
Case Study: The Ghost in the Acadia
A 2009 GMC Acadia came into my bay with a bizarre set of symptoms the owner had been chasing for months. It would randomly lose power, the dash would light up like a Christmas tree, and it threw a dozen different communication (U-series) codes. Other shops had replaced sensors and even a throttle body to no avail. After confirming the network wiring was solid, I focused on the ECM. On the surface, it seemed okay, but under load testing, its internal voltage regulation would dip erratically. This tiny fluctuation was enough to crash the communication network. We installed a VIN-programmed ECM, and every single issue vanished. It’s a classic example of how a failing 2008-2009 STS ECM (and its counterparts) can create system-wide chaos that looks like anything but the module itself.
Common Signs of a Failing Engine Control Module
If you’re experiencing any of the following, your ECM could be the root cause. A failing module can often trigger diagnostic trouble codes (DTCs) such as P0601, P0606, or various U-codes for loss of communication.
- ✔ Check Engine Light is on or flashing
- ✔ Engine stalling, sputtering, or misfiring
- ✔ Vehicle won’t start or is very difficult to start
- ✔ Noticeable decrease in fuel economy
- ✔ Poor or erratic automatic transmission shifting
- ✔ Loss of communication with other vehicle modules
- ✔ Apparent failure of multiple unrelated sensors at once
A Straightforward Guide to Installation
Replacing your ECM is a manageable job for a confident DIYer. With our pre-programming service, the most difficult step is already done for you. Just follow these general steps for a successful installation.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait 10-15 minutes to allow all modules to power down completely.
- Locate the ECM: On these vehicles, the ECM is typically found in the engine compartment. For the Cadillac STS/CTS, it’s on the right-hand (passenger) side. For the GM SUVs (Acadia, Enclave, Traverse), it’s often located behind the fan shroud.
- Disconnect Connectors: Carefully release the locking tabs and unplug the large wiring harness connectors from the old module. Inspect the connectors for any corrosion or damage.
- Remove the Old Module: Unbolt the mounting hardware holding the original ECM in place and remove it from the vehicle.
- Install the New Module: Mount your new, pre-programmed ECM in the same location and secure it with the original hardware.
- Reconnect Everything: Plug the wiring harness connectors firmly into the new module until they click into place. Reconnect the negative battery terminal.
- Final Steps: Some vehicles may require a security relearn procedure, which can typically be done without special tools. Turn the key to the ‘ON’ position for 10-15 minutes, then off, and then start the engine. Your vehicle is now ready to drive.
Verified Vehicle Compatibility
This module is a direct-fit replacement for several GM cars and SUVs. It is compatible with part numbers 12623325, 12628387, 12605672, 12630594, and 19300016. Please verify your vehicle is on the list below. Providing your VIN at checkout is required to ensure perfect programming.
- 2008 Cadillac CTS (3.6L, VIN V – 8th digit)
- 2009 Cadillac CTS (3.6L, VIN V – 8th digit)
- 2008 Cadillac STS (3.6L)
- 2009 Cadillac STS (3.6L)
- 2009 GMC Acadia
- 2009 Buick Enclave
- 2009 Saturn Outlook
- 2009 Chevrolet Traverse
Frequently Asked Questions
Do I need to do any programming after I receive this module?
No! This is the biggest benefit. We program the module to your specific VIN before we ship it. It arrives ready to install, saving you a trip to the dealer and hundreds in programming fees.
What is a VIN and where do I find it?
The VIN (Vehicle Identification Number) is a unique 17-digit code for your car. You can find it on your driver’s side dashboard (visible through the windshield), on the driver’s side door jamb sticker, or on your vehicle’s registration and insurance documents.
Will this fix my Check Engine Light?
If the Check Engine Light is caused by a faulty ECM (common codes P0601-P0606), then yes, this module will resolve the issue. However, you should always have the codes read to ensure the problem isn’t a separate sensor or component.
Is this a difficult part to install myself?
For someone with basic mechanical skills, this is a very manageable job. The most important parts are disconnecting the battery and carefully handling the electrical connectors. Since the programming is done, it’s essentially a plug-and-play replacement.
What if my original part number is not 12623325?
This module is also a direct replacement for part numbers 12628387, 12605672, 12630594, and 19300016. As long as your vehicle and original part number are on our compatibility list, this module will work perfectly.