Restore Your GM Truck’s Performance and Reliability
Is your 2011 Sierra, Silverado, or even your Cruze acting up? If you’re dealing with frustrating issues like stalling, a persistent check engine light, rough idling, or a no-start condition, the problem often points directly to a failing Engine Control Module (ECM). As the brain of your vehicle’s engine, a faulty ECM can cause a cascade of problems that leave you stranded. This isn’t just an inconvenience; it’s a critical failure that compromises your vehicle’s performance and safety. I’ve seen it hundreds of times in my shop—a great engine crippled by a bad computer.
This is your direct, hassle-free solution. We offer a reliable Engine Control Module, part number 12642100, that arrives at your door completely programmed for your specific vehicle. Simply provide us with your Vehicle Identification Number (VIN) after your purchase, and our technicians will flash the unit with the latest, most stable GM-certified software. This means no expensive trips to the dealership for programming. You get a part that’s ready for installation right out of the box, restoring your engine’s proper function, fuel efficiency, and power.
From the Diagnostic Bay: The Intermittent No-Start Nightmare
A customer brought in his 2011 Silverado 2500 with the 6.0L V8. The complaint was a classic head-scratcher: it would start perfectly for a week, then refuse to crank for a day. No rhyme or reason. He’d already replaced the battery and checked the starter. When we got it, of course, it started fine. But a deep scan revealed stored communication codes (U0100 – Lost Communication with ECM) and a history of internal processor faults (P0606). These are tell-tale signs of an ECM on its last legs. The internal circuits were failing intermittently. Instead of a complex and costly diagnostic chase, we recommended a pre-programmed ECM. The customer installed it himself in under 30 minutes. That was six months ago, and the truck hasn’t missed a beat since. It’s a prime example of how the right part saves time, money, and a lot of headaches.
Is Your Vehicle Showing These Symptoms?
A failing ECM can manifest in many ways. If you’re experiencing any of the following, this module is the likely solution:
- ✔ Check Engine Light is illuminated with codes like P0601, P0602, P0606 (Internal Control Module Errors) or U-series communication codes.
- ✔ The engine cranks but will not start.
- ✔ Severe drop in fuel economy for no apparent reason.
- ✔ Engine stalling, sputtering, or hesitating during acceleration.
- ✔ Transmission shifting issues or harsh engagement.
- ✔ Apparent loss of spark or fuel injector pulse.
A Straightforward Guide to Installation
Installing your new ECM is a job most DIYers can handle with basic tools. Following these steps will ensure a smooth process.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait at least 10 minutes to allow the system to fully discharge.
- Locate the ECM: On the 2011 GM HD trucks, the ECM is typically located in the front of the engine bay on the driver’s side (LH side), near the battery or airbox.
- Disconnect the Connectors: Carefully release the locking tabs on the wiring harness connectors and pull them straight out from the module. Do not force them. Inspect the connectors for any corrosion or damage.
- Remove the Old Module: Unbolt the old ECM from its mounting bracket. There are usually a few bolts holding it in place.
- Install the New ECM: Mount your new, pre-programmed ECM onto the bracket and secure it with the bolts.
- Reconnect Everything: Firmly plug the wiring harnesses back into the new module until they click into place. Reconnect the negative battery terminal.
- Final Step: Some vehicles may require a security relearn procedure, which can often be done without a scan tool by cycling the key. Instructions are widely available online for your specific model. Now, start the engine and enjoy restored performance!
Verified Vehicle Compatibility
This module is a direct fit for the following vehicles and is a replacement for part numbers 12616532, 12642100, and 12656958. Please ensure your vehicle is on this list:
2011 Chevrolet Silverado 2500/3500 Pickup: Electronic Control Module; (LH front engine compartment), 6.0L
2011 GMC Sierra 2500/3500 Pickup: Electronic Control Module; (LH front engine compartment), 6.0L
2011 GMC Sierra Denali 2500/3500: Electronic Control Module; (LH front engine compartment), 6.0L
Frequently Asked Questions About This ECM
Frequently Asked Questions
Do I need to do any programming or flashing myself?
No. This is the biggest benefit of our service. We program the ECM with your vehicle’s VIN and the latest GM software before it ships. It arrives ready to install.
How do I provide my VIN?
After you complete your purchase, we will send you an email with instructions on how to reply with your vehicle’s 17-digit VIN. We cannot ship the module until we have this information.
What is the condition of this ECM?
This is a high-quality, fully tested Engine Control Module, guaranteed to perform to OEM standards. We load it with the latest GM-certified software for your specific vehicle to ensure reliability.
My original part number is 12616532. Will this part work?
Yes. This ECM, part number 12642100, is a fully compatible and interchangeable replacement for part numbers 12616532 and 12656958, covering the same applications.
Where is the ECM located on my 2011 Sierra 2500?
You will find the ECM in the engine compartment, mounted on the front driver’s side (LH side).