Restore Peak Performance to Your GM Truck or SUV with a VIN-Programmed Engine Control Module
Dealing with a frustrating no-start condition, erratic engine behavior, or a stubborn check engine light on your 2018 GMC Yukon XL 1500? As a technician with over two decades of experience, I’ve seen firsthand how a failing Engine Control Module (ECM) can bring an otherwise solid vehicle to a standstill. This isn’t just an inconvenience; it’s a critical failure that compromises performance and reliability. This ECM, part number 12704475, is the definitive solution, arriving at your door pre-programmed with the latest GM software specifically for your vehicle’s VIN.
We handle the complex programming for you, saving you a costly trip to the dealership and hours of diagnostic headaches. By providing your Vehicle Identification Number (VIN) at checkout, you ensure this module is a perfect match, loaded with the correct calibrations for your specific engine and options. This is the most direct path to getting your truck, van, or SUV running correctly again.
Is Your Vehicle Exhibiting These ECM Failure Symptoms?
- ✔ Unexplained engine stalling or shutting off while driving.
- ✔ Complete no-start condition where the engine cranks but won’t fire up.
- ✔ Noticeable decrease in fuel economy and poor engine performance.
- ✔ Check Engine Light with communication-related Diagnostic Trouble Codes (DTCs) like U0100.
- ✔ Internal processor failure codes stored, such as P0601, P0602, or P0606.
- ✔ Erratic automatic transmission shifting or other strange electrical issues.
A Technician’s Notebook
I recently had a 2018 Sierra 1500 in the shop with a classic, frustrating intermittent no-start. The owner had already replaced the battery and starter to no avail. On my scan tool, I could see the ECM would randomly drop offline, losing communication with the rest of the vehicle’s modules. After verifying the power and ground circuits to the ECM were solid, the diagnosis was clear: internal module failure. We ordered a VIN-programmed ECM like this one. Once it arrived, the physical swap took less than 15 minutes, and after performing the security relearn, the truck fired up instantly and has been reliable ever since. This is the right way to fix the problem.
A Straightforward Guide to Installation
Replacing the ECM is a manageable job for a confident DIYer or any professional technician. Follow these general steps for a successful installation.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the ECM: On the 2018 Yukon XL 1500, the ECM is typically found in the left (driver’s side) front of the engine compartment.
- Disconnect Connectors: Carefully release the locking tabs and unplug the main electrical harnesses from the old ECM. Inspect them for any corrosion or damage.
- Remove the Old Module: Unbolt the ECM from its mounting bracket and remove it from the vehicle.
- Install the New ECM: Mount your new, pre-programmed ECM securely onto the bracket and reconnect the electrical harnesses, ensuring they click firmly into place.
- Reconnect Battery: Reattach the negative battery terminal.
- Perform Security Relearn: This is a critical final step. If the vehicle does not start, you must perform a Vehicle Theft Deterrent (VTD) relearn using a GM-compatible programming system like TIS2Web or Techline Connect. This syncs the new ECM with your vehicle’s immobilizer system. Other procedures like a Crankshaft Variation Relearn may also be necessary.
IMPORTANT NOTICE: While we program the module to your VIN, the final security relearn and any other setup procedures are the responsibility of the installer. This is a standard requirement for this type of repair.
Verified Vehicle Compatibility
This module is the correct replacement for a wide range of GM vehicles. We confirm exact fitment using your VIN, but it is engineered to work with the following models and options:
- ✔ 2018-2019 Corvette: (RH cowl under dash)
- ✔ 2018 Silverado 1500 / Sierra 1500: (LH front engine compartment)
- ✔ 2018 Escalade & Escalade ESV: (Engine compartment)
- ✔ 2018 Express / Savana 2500 & 3500 Vans: (LH rear engine compartment), 4.3L
- ✔ 2018 Suburban 1500 / Tahoe: (LH front engine compartment)
- ✔ 2018 Yukon & Yukon XL 1500: (LH front engine compartment)
- ✔ 2018 Sierra Denali 1500: (LH front engine compartment)
- ✔ 2018 Cadillac XTS: (3.6L, VIN 8, opt LF3)
Why do you need my vehicle’s VIN?
Why do you need my vehicle’s VIN?
Your VIN is essential for us to load the exact, factory-correct software and calibrations for your vehicle’s specific engine, transmission, and emissions equipment. This ensures proper function and avoids compatibility issues.
What is a security relearn and is it difficult?
A security relearn (or VTD relearn) syncs the new ECM to your vehicle’s anti-theft system. It is a mandatory step for the vehicle to start and run. It is not difficult but requires a professional scan tool with access to GM’s TIS2Web or Techline Connect software. Most professional repair shops can perform this procedure.
My original part number is 12680656. Will this part 12704475 work?
Yes. This ECM, part number 12704475, is the updated and correct service replacement for several older part numbers, including 12680656, 12692069, 12686383, and 12688528. We verify the perfect match with your VIN.
Can I perform the relearn procedure myself?
Unless you have access to a professional-grade diagnostic tool with a subscription to GM’s service software, you will likely need to have a qualified mechanic or dealership perform the final relearn procedures. This is a standard part of replacing a modern ECM.