Is Your 2017 GMC Terrain Running Rough?
A failing Engine Control Module (ECM), the brain of your vehicle, can be the source of countless frustrating and difficult-to-diagnose issues. From a sudden refusal to start to a persistent Check Engine Light that no amount of part-swapping seems to fix, a faulty ECM can bring your daily drive to a grinding halt. If you’re experiencing erratic engine behavior, poor fuel economy, or mysterious electrical gremlins in your 2017 Terrain or other compatible GM vehicle, you’ve found the definitive solution. This isn’t just a replacement part; it’s a restoration of your vehicle’s core functionality, programmed specifically for you.
From the Diagnostic Bay
We had a 2017 Equinox come in with a persistent, random cylinder misfire (P0300) that was driving the owner crazy. They had already replaced all the spark plugs, ignition coils, and even a fuel injector. The misfire would come and go, with no discernible pattern. After hours of diagnostics, we hooked up a scope to the injector control circuits at the ECM connector. We found that the signal for cylinder 3’s injector would intermittently drop out. The injector itself was fine, the wiring was perfect—the fault was internal to the ECM’s driver circuit. A replacement, programmed ECM like this one solved the problem instantly. It’s a classic case where the root cause is the computer itself, not the components it controls.
Symptoms of a Failing Engine Control Module
If your vehicle is exhibiting any of the following symptoms, a failing ECM could be the culprit. Confirming the diagnosis with a professional is always recommended, but these are the most common indicators:
- ✔ Check Engine Light: The light is on, and you may have codes that are inconsistent or point to multiple sensor failures simultaneously.
- ✔ Engine Stalling or Misfiring: The engine may stall for no reason, run rough, or misfire, leading to poor performance and hesitation.
- ✔ No-Start Condition: The engine cranks but refuses to start. This can be caused by the ECM failing to control the fuel or spark systems.
- ✔ Poor Fuel Economy: A sudden and unexplained drop in your vehicle’s MPG can be a sign the ECM is not managing the engine’s fuel mixture correctly.
- ✔ Shifting Problems (Automatic Transmission): The ECM works with the Transmission Control Module (TCM). A faulty ECM can cause harsh shifting, failure to shift, or getting stuck in gear.
- ✔ Loss of Communication: A mechanic’s scan tool may be unable to communicate with the ECM, a definitive sign of an internal failure.
Why Choose Our Programmed 2017 Terrain ECM?
This isn’t just another off-the-shelf computer. We provide a comprehensive, plug-and-play solution designed to get you back on the road with minimal hassle. When you order from us, you’re getting an Engine Control Module that is meticulously tested and loaded with the latest, most stable software updates directly from GM. We use the Vehicle Identification Number (VIN) you provide to flash the module, ensuring it matches your vehicle’s specific configuration, options, and security protocols. This critical step eliminates the need for an expensive trip to the dealership for additional programming or key relearning procedures. It arrives at your door ready for installation.
Guaranteed Fitment
This module is a direct replacement for part numbers 12667002, 12666070, and 12667189. It is guaranteed to fit the following vehicles:
- 2017 Buick Enclave (Electronic Control Module; behind fan shroud)
- 2017 Buick LaCrosse (Electronic Control Module; 3.6L)
- 2017 Buick Regal (Electronic Control Module; LH engine compartment)
- 2017 Buick Verano (Electronic Control Module)
- 2017 Cadillac XTS (Electronic Control Module; 3.6L, VIN 3, opt LFX)
- 2017 Chevrolet Caprice (Electronic Control Module; 3.6L)
- 2017 Chevrolet Equinox (Electronic Control Module; LH engine compartment)
- 2017-2019 Chevrolet Impala (Electronic Control Module)
- 2017 Chevrolet Traverse (Electronic Control Module; behind fan shroud)
- 2017 GMC Acadia (Electronic Control Module; VIN J, Limited, behind fan shroud)
- 2017 GMC Terrain (Electronic Control Module; LH engine compartment)
Frequently Asked Questions
Do I need to do any programming or flashing myself?
No. This ECM comes fully programmed to your vehicle’s specific VIN. It is a true plug-and-play solution. You will not need a scan tool or a trip to the dealer for programming.
Where is the ECM located on my 2017 GMC Terrain?
On the 2017 GMC Terrain, the Engine Control Module is typically located in the engine compartment on the left-hand (driver’s) side. Always disconnect the battery before attempting to remove or install any electronic modules.
How do I provide my VIN?
After you complete your purchase, you will need to send us your 17-digit Vehicle Identification Number (VIN). You can typically find this on your vehicle’s registration, insurance card, or on a plate on the driver’s side dashboard visible through the windshield.
What if my original part number is slightly different?
This module directly replaces part numbers 12667002, 12666070, and 12667189. As long as your vehicle is on the compatibility list, this module will function correctly once programmed to your VIN, even if your original part number differs.
Will this fix my Check Engine Light?
If the Check Engine Light and associated fault codes are being caused by a faulty ECM, then this part will resolve the issue. It is crucial to have a proper diagnosis performed to ensure the ECM is the root cause and not a separate sensor or wiring problem.