Restore Your Vehicle’s Brain and Get Back on the Road
Is your Chevrolet, Buick, or GMC vehicle acting up? Unexplained stalling, a persistent Check Engine Light, or a frustrating no-start condition can often point to one critical component: the Engine Control Module (ECM). As an automotive technician with over two decades of experience, I’ve seen firsthand how a failing ECM can disrupt your entire vehicle, turning a reliable ride into a source of constant worry. This isn’t just a part; it’s the central computer that manages everything from fuel injection and ignition timing to emissions and transmission shifting. When it fails, your vehicle’s performance suffers dramatically.
This replacement Engine Control Module, corresponding to part number 12670335, is the definitive solution. We take the biggest headache out of the repair process by programming the module specifically for your vehicle using your VIN. This ensures it arrives with the latest GM factory software updates, ready for a straightforward installation. You get a reliable, effective repair without the high costs and scheduling hassles of a dealership visit. This is the same process we use in the shop to guarantee a fix that lasts.
A Technician’s Notebook: The Phantom Electrical Gremlin
I remember a 2014 Chevy Cruze that came into the bay with a laundry list of intermittent problems—stalling at lights, erratic shifting, and a Check Engine Light that would come and go. The owner had already replaced the battery and alternator. Our scans showed a slew of communication error codes (U-codes) that didn’t point to a single sensor. After checking the main harness for damage, we suspected the ECM. On a hunch, we used a heat gun on the module, and sure enough, the engine sputtered and died. The internal circuits were failing under thermal stress. We replaced it with a VIN-programmed module just like this one, and the car ran perfectly. It’s a classic failure mode for these ECMs across multiple GM platforms.
Common Symptoms of ECM Failure
If you’re experiencing any of the following, a faulty ECM could be the culprit. Confirming these symptoms can save you time and money on unnecessary diagnostics.
- ✔ The Check Engine Light is illuminated, often with internal processor fault codes like P0601 or P0606.
- ✔ Your vehicle refuses to start or has very difficult, intermittent starting issues.
- ✔ A noticeable drop in fuel economy and overall engine performance.
- ✔ The engine stalls for no reason, either while driving or at idle.
- ✔ Transmission shifting feels harsh, erratic, or delayed.
- ✔ Loss of communication with the module when using a diagnostic scan tool (U0100).
Your Straightforward Installation Guide
Installing your new ECM is a manageable task for a confident DIYer. By following these steps, you can avoid a trip to the shop. Always consult a repair manual for your specific vehicle’s torque specs and procedures.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before beginning any electrical work.
- Locate the ECM: Find the old Engine Control Module. On many of these vehicles, it’s located in the engine compartment, often on the firewall or inner fender.
- Disconnect the Harnesses: Carefully release the locking tabs and unplug the main electrical connectors from the module. Inspect them for any corrosion or damage.
- Remove the Old Module: Unbolt the faulty ECM from its mounting bracket and remove it from the vehicle.
- Install the New Module: Secure your new, pre-programmed module onto the mounting bracket. Ensure it is seated correctly.
- Reconnect and Secure: Plug the wiring harnesses back into the new ECM until they click securely in place. Reconnect the negative battery terminal.
- Final Steps: In some cases, a security relearn or crankshaft position sensor variation relearn procedure may be required. This can often be initiated with a sequence of key turns or may require a capable scan tool.
Will This Fit My Vehicle?
This module is a direct replacement for part number 12670335 and is compatible with a wide range of GM vehicles. Please verify your vehicle is on this list before ordering. Providing your VIN is mandatory so we can ensure perfect compatibility and programming.
CRUZE 16 Electronic Control Module; VIN P (4th digit, Limited)
SONIC 12 Electronic Control Module; 1.4L
ELR 14-16 Electronic Control Module; gasoline, (LH rear engine compartment)
EXPRESS 3500 VAN 16 Electronic Control Module; (LH rear engine compartment), 4.8L
CRUZE 12 Electronic Control Module; 1.4L
CRUZE 15 Electronic Control Module; gasoline, ID 12668866
SONIC 15 Electronic Control Module; ID 12668866
TRAX 13-14 Electronic Control Module; 1.4L
SONIC 13 Electronic Control Module; ID 12643636
EXPRESS 3500 VAN 16 Electronic Control Module; (LH rear engine compartment), 6.0L
SAVANA 3500 VAN 16 Electronic Control Module; (LH rear engine compartment), 6.0L
EXPRESS 2500 VAN 16 Electronic Control Module; (LH rear engine compartment), 6.0L
SONIC 14 Electronic Control Module; (ID 12643636)
EXPRESS 2500 VAN 16 Electronic Control Module; (LH rear engine compartment), 4.8L
SILVERADO 2500 PICKUP 12-16 Electronic Control Module; (LH front engine compartment), 6.0L
SILVERADO 3500 PICKUP 12-16 Electronic Control Module; (LH front engine compartment), 6.0L
VOLT 11-15 Electronic Control Module; gasoline, (LH rear engine compartment)
SAVANA 2500 VAN 16 Electronic Control Module; (LH rear engine compartment), 4.8L
CRUZE 14 Electronic Control Module; gasoline
SAVANA 2500 VAN 16 Electronic Control Module; (LH rear engine compartment), 6.0L
SONIC 16 Electronic Control Module
CRUZE 13 Electronic Control Module
ENCORE 15 Electronic Control Module; (1.4L), ID 12643636
ENCORE 16 Electronic Control Module; (1.4L), VIN B (8th digit, opt LUV)
SAVANA 3500 VAN 16 Electronic Control Module; (LH rear engine compartment), 4.8L
SIERRA 2500 PICKUP 12-16 Electronic Control Module; (LH front engine compartment), 6.0L
SIERRA 3500 PICKUP 12-16 Electronic Control Module; (LH front engine compartment), 6.0L
TRAX 15-16 Electronic Control Module
SIERRA DENALI 2500 12-15 Electronic Control Module; (LH front engine compartment), 6.0L
SUBURBAN 3500 16 Electronic Control Module; (LH front engine compartment)
ENCORE 13-14 Electronic Control Module; (1.4L)
SPARK 14-15 Electronic Control Module; gasoline model
SIERRA DENALI 3500 12-16 Electronic Control Module; (LH front engine compartment), 6.0L
ENCORE 15 Electronic Control Module; (1.4L), ID 12668866
SONIC 15 Electronic Control Module; ID 12643636