Restore Peak Performance to Your GM Vehicle
Is your Cadillac XTS, Corvette, or Silverado plagued by frustrating issues like intermittent stalling, a persistent check engine light, or a complete no-start condition? You’re not alone. The Engine Control Module (ECM) is the brain of your vehicle’s engine, and when it fails, it 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 reliability. We offer a direct-fit, dependable solution: a genuine GM Engine Control Module, part number 12704475, professionally programmed to your vehicle’s specific VIN.
Case Study: A Tricky Diagnosis
I recently had a 2018 Sierra 1500 in my bay that was driving the owner crazy. It would randomly lose power and throw a flurry of communication codes (U-codes) along with a P0606 (ECM/PCM Processor Fault). We checked all the basics—wiring harnesses, grounds, power feeds—and everything looked solid. After hours of diagnostics, we connected a scope to the CAN bus lines and saw a noisy, erratic signal originating from the ECM. The internal processor was failing intermittently under load. Swapping in a pre-programmed ECM like this one resolved all the issues instantly. The client was back on the road the same day, avoiding a costly and time-consuming trip to the dealer.
Is Your GM Vehicle Showing These Signs of ECM Failure?
A failing ECM can manifest in various ways. If you’re experiencing any of the following, it’s a strong indicator that your engine computer may need replacement. Catching it early can prevent further damage to other components.
- ✔ No-start or hard-starting conditions where the engine cranks but won’t fire up.
- ✔ Unexplained drop in fuel economy or engine performance.
- ✔ The check engine light is on with codes like P0601, P0606, or other internal processor faults.
- ✔ Stalling for no apparent reason, either at idle or while driving.
- ✔ Transmission shifting issues or erratic behavior.
- ✔ Communication errors with scan tools or other modules.
Your Straightforward Guide to Installing the 2018 XTS Engine Control Module
Replacing your ECM is a manageable job for a confident DIYer or any professional technician. Our pre-programming service handles the most complex step, but proper installation is key. Follow these steps carefully.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait at least 15 minutes for the system to fully discharge before proceeding.
- Locate the ECM: The location varies by model. On a 2018 Cadillac XTS, it’s typically accessible in the engine bay. For other models like the Silverado or Tahoe, it’s on the LH front of the engine compartment. For the Corvette, check the RH cowl area under the dash.
- Disconnect and Remove: Carefully unplug the electrical connectors. Most have a locking tab that needs to be released. Once disconnected, unbolt the old ECM from its mounting bracket and remove it from the vehicle.
- Install the New ECM: Mount the new, pre-programmed ECM securely in place. Reconnect the electrical connectors, ensuring they click firmly into place.
- Reconnect the Battery: Reattach the negative battery terminal and tighten it securely.
- Perform Relearn Procedures: This is a critical final step. Attempt to start the vehicle. If it does not start, a Vehicle Theft Deterrent System (VTDS) relearn is required. This must be done with a professional tool like GM’s TIS2WEB/Techline Connect. Additionally, other procedures like a Crankshaft Position Variation Relearn or injector flow rate programming may be necessary depending on your specific vehicle and its condition. This is the responsibility of the installer.
Verified Compatibility for Your GM Vehicle
This ECM is a direct replacement for multiple part numbers, ensuring broad compatibility. Please verify your vehicle and options below. This module fits part numbers 12704475, 12692069, 12680656, 12686383, and 12688528.
- 2018 Cadillac Escalade / Escalade ESV
- 2018 Cadillac XTS (3.6L with VIN 8, opt LF3)
- 2018-2019 Chevrolet Corvette (VIN 6/LT4 or VIN 7/LT1)
- 2018 Chevrolet Express 2500 / 3500 Van (4.3L)
- 2018 Chevrolet Silverado 1500 Pickup (ID 12680656)
- 2018 Chevrolet Suburban 1500
- 2018 Chevrolet Tahoe
- 2018 GMC Savana 2500 / 3500 Van (4.3L)
- 2018 GMC Sierra 1500 Pickup (ID 12680656)
- 2018 GMC Sierra Denali 1500 (ID 12686383)
- 2018 GMC Yukon / Yukon XL 1500
Do I need to do anything after I buy this ECM?
Do I need to do anything after I buy this ECM?
Yes. After you complete your purchase, you MUST provide us with your 17-digit Vehicle Identification Number (VIN). We use this to program the module with the latest GM-certified software for your exact vehicle configuration before we ship it.
What if my car doesn’t start after installation?
If the vehicle fails to start, it’s almost always because the Vehicle Theft Deterrent System (VTDS) needs to be relearned. This security handshake between the ECM and other modules is a standard procedure and requires a professional scan tool with access to GM’s TIS2WEB or Techline Connect service.
Are other relearns required besides the theft system?
Possibly. Depending on your vehicle and the original reason for failure, you or your mechanic may need to perform additional setup procedures. Common examples include the Crankshaft Variation Relearn (CASE relearn) or programming injector flow rates. This is the responsibility of the installer.
How do I know if this ECM will fit my vehicle?
This module, part number 12704475, replaces several other part numbers including 12688528. Please check our detailed fitment list. The best way to ensure compatibility is to match the part number from your old module to one of the numbers listed here.