Is your 2003-2007 Sierra, Silverado, or other GM truck frustrating you with baffling electrical problems? If you’re dealing with a no-start condition, random stalling, harsh shifting, or a check engine light that just won’t go away, the problem often points directly to a failing Powertrain Control Module (PCM). As a technician with over two decades of experience under the hood, I’ve seen how a faulty PCM—the brain of your vehicle’s engine and transmission—can cause chaos. Don’t replace part after part chasing ghosts in the machine. Get the definitive solution with this reliable, VIN-programmed PCM.
This isn’t just a replacement part; it’s a restoration of your truck’s core functionality. We take the hassle and high cost of dealership programming out of the equation. Simply provide us with your vehicle’s VIN during checkout, and our experts will flash this module with the very latest GM factory software updates specific to your truck. This ensures all systems—from fuel delivery and ignition timing to transmission shift points—operate exactly as the manufacturer intended. This process often corrects underlying software bugs from the original factory programming that can contribute to premature failure.
Is Your Truck Showing These Symptoms?
A failing PCM can manifest in numerous ways, often mimicking other component failures. If you’re experiencing any of the following, it’s a strong indicator that your engine computer is the culprit. In the shop, we frequently see these issues tied to internal PCM faults.
- ✔ Check Engine Light is on with communication codes (like U0100) or internal processor codes (P0601, P0602, P0606).
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained stalling, especially after the engine has warmed up.
- ✔ Noticeably poor fuel economy and reduced engine power.
- ✔ Harsh, erratic, or delayed automatic transmission shifting.
- ✔ Other modules in the vehicle cannot communicate with the PCM.
- ✔ The vehicle fails to pass an emissions test.
Case Study: The Ghost in the Suburban
A customer brought in a 2005 Suburban 2500 with a 6.0L that had the most frustrating intermittent stalling issue. It would run perfectly for days, then die at a stoplight without warning. No codes were stored initially. They had already replaced the fuel pump and crank sensor. I hooked up my scan tool and monitored live data. After letting it run in the bay for 45 minutes, I saw the 5-volt reference signal to the sensors suddenly drop to zero, and the engine died instantly. This pointed directly to an internal short in the PCM that only appeared when it got hot. A new, properly programmed PCM like this one solved the problem permanently. It’s a classic failure mode for these units, especially when located under the battery where heat and potential acid leaks can take their toll.
A Straightforward Guide to Installation
Replacing the PCM on these GM trucks is a job most DIYers can handle with basic tools. Our pre-programming service saves you the most difficult step. Please note: After installation, a Crankshaft Variation Relearn (also known as a CASE Relearn) is required using a compatible scan tool to prevent a P1336 trouble code. Many local shops can perform this service for a small fee.
- Safety First: Disconnect the negative terminal from your vehicle’s battery.
- Locate the PCM: On most of these trucks and SUVs, the PCM is located on the driver’s side, in the engine bay, under or next to the battery tray.
- Disconnect Connectors: Carefully unclip and remove the electrical wiring harnesses from the old PCM. The levers on the connectors make this easier; do not force them.
- Remove the Old Module: Unbolt the PCM from its mounting bracket and remove it from the vehicle.
- Install the New PCM: Mount your new, VIN-programmed PCM into the bracket and securely re-attach the wiring harnesses. Ensure they click into place.
- Reconnect Battery: Re-attach the negative battery terminal.
- Perform CASE Relearn: Start the vehicle. It should run, but you will need to have the Crankshaft Variation Relearn procedure completed to sync the new PCM with your engine’s crankshaft position sensor.
Verified Vehicle Compatibility
This module, part number 12602802, is a direct replacement for several service numbers including 89017750, 12582605, 12589463, 89017734, and 28042802. It fits a wide range of GM vehicles. Please confirm your model and options below. Matching the ID number is critical for some 2004 models.
CADILLAC ESCALADE, ESV, EXT (03-06)
CHEVROLET SSR (03)
SILVERADO 1500, 2500, 3500 (03-07 Classic)
SUBURBAN 1500, 2500 (03-06)
TAHOE (03-06)
GMC SIERRA 1500, 2500, 3500 (03-07 Classic)
SIERRA DENALI (03-07 Classic)
YUKON, YUKON XL 1500, YUKON XL 2500 (03-06)
HUMMER H2 (03-07)
ISUZU ASCENDER (03, 5.3L)
GMC ENVOY XL (03, 5.3L)
CHEVROLET TRAILBLAZER EXT (03, 5.3L)
Note: Please verify specific options like engine size and ID numbers as listed in the full compatibility chart.
Frequently Asked Questions
Do I need to do anything after installing this PCM?
Yes. While our VIN programming handles the main software, you must have a Crankshaft Variation Relearn (CASE Relearn) performed with a capable scan tool. This synchronizes the PCM to your specific engine to prevent misfire detection codes. Additionally, some vehicles may require a security relearn procedure, which can typically be done without special tools.
How do I provide my VIN?
After you complete your purchase, you will receive instructions on how to send us your 17-digit Vehicle Identification Number (VIN). We cannot program and ship your module without it.
Is this a plug-and-play part?
It is nearly plug-and-play. It will plug in directly and start the vehicle. However, the mandatory CASE relearn is the final step to make it fully operational and prevent a check engine light for code P1336.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM also controls transmission functions, including shift points and line pressure. If your shifting problems are caused by a faulty computer, this module, loaded with fresh software, is the correct fix. It will not fix internal mechanical transmission failures.
What if my part number is slightly different?
This module (12602802) replaces several older service numbers like 89017750 and 12589463. As long as your vehicle is on the compatibility list and your original part is one of the listed service numbers, this module is the correct, updated replacement.