Get Your GM Truck Running Reliably Again
Is your 2003-2007 Silverado 3500, or another compatible GM truck, giving you headaches? If you’re dealing with frustrating issues like a persistent check engine light, poor engine performance, stalling, or a complete no-start condition, a failing Powertrain Control Module (PCM) is a very common culprit. As the central computer of your vehicle, the PCM controls everything from fuel mixture and ignition timing to transmission shifting. When it fails, the symptoms can be unpredictable and difficult to diagnose. This replacement PCM, part number 12602802, is the definitive solution to restore your truck’s performance and reliability.
From the Diagnostic Bay: The Case of the Intermittent Stall
I remember a 2005 Sierra 2500 with the 6.0L engine that came into my shop. The owner was at his wit’s end. The truck would run perfectly for days, then suddenly stall at a red light and refuse to restart for 10-15 minutes. No consistent codes were stored, just a random U0100 (Lost Communication with ECM/PCM) every so often. We checked grounds, wiring, and power feeds—all solid. The problem was heat soak. After a long drive, the internal processors of the original PCM would overheat and fail. Once it cooled, it worked again. This is a classic failure I’ve seen dozens of times on these GM trucks. Swapping in a quality, properly programmed PCM like this one solved the problem for good.
Is Your Truck Showing These Telltale Signs?
A failing PCM can manifest in many ways. If you’re experiencing any of the following, it’s time to consider a replacement. Proper diagnosis is always recommended, but these are strong indicators of a bad engine computer.
- âś” Check Engine Light is on with codes like P0601, P0602, P0606 (Internal Control Module Processor Error).
- âś” Engine cranks but will not start.
- âś” Rough or unpredictable shifting from the transmission.
- âś” Unexplained drop in fuel economy.
- âś” Intermittent stalling or engine hesitation.
- âś” Communication errors with scan tools (U-codes).
A Straightforward Guide to Installation
One of the best features of this module is that it arrives programmed to your vehicle’s VIN, eliminating the need for an expensive trip to the dealership. Installation is a job most DIYers can handle in their own garage.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before beginning any electrical work.
- Locate the PCM: On most of these trucks and SUVs, the PCM is located in the engine bay on the driver’s side, often under or next to the battery tray.
- Disconnect the Harnesses: Carefully unclip and remove the electrical connectors from the old PCM. Inspect them for any corrosion or damage.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket and remove it from the vehicle.
- Install the New PCM: Mount your new, pre-programmed PCM and securely reconnect the electrical harnesses.
- Reconnect the Battery: Re-attach the negative battery terminal.
- Perform Security Relearn: In many cases, you will need to perform a simple security relearn procedure (often called a Passlock or Passkey relearn) to sync the new PCM with your vehicle’s anti-theft system. This procedure typically involves turning the key to the ‘ON’ position for 10-15 minutes and can be done without special tools.
Verified Vehicle Compatibility
This module is a direct replacement for service number 12602802 and is compatible with a wide range of General Motors trucks and SUVs. Please verify your part number or contact us with your VIN if you are unsure. This part fits the following vehicles, among others:
- Chevrolet Silverado 1500, 2500, 3500 (2003-2007 Classic)
- GMC Sierra 1500, 2500, 3500 (2003-2007 Classic)
- Chevrolet Tahoe & Suburban (2003-2006)
- GMC Yukon & Yukon XL (2003-2006)
- Cadillac Escalade, ESV, EXT (2003-2006)
- Hummer H2 (2003-2007)
- Chevrolet Avalanche (2003-2006)
- And more. A detailed list is provided in the fitment chart.
Frequently Asked Questions
What do I need to do after I purchase this PCM?
After you place your order, you must provide us with your vehicle’s 17-digit VIN (Vehicle Identification Number). We use this to load the correct, updated GM software for your specific engine, transmission, and options before we ship the module to you.
Is this part truly plug-and-play?
Yes, for the most part. Because it comes pre-programmed, you will not need a dealer-level scan tool. However, you will likely need to perform a simple key-cycle security relearn procedure that takes about 30 minutes to sync the module to your truck’s anti-theft system. Instructions are readily available online for this process.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the PCM (like code P0601), then yes, this will resolve the issue. However, you must ensure the problem isn’t with a sensor or wiring. A proper diagnosis is always the best first step.
Is this compatible with other part numbers?
Yes, this PCM with service number 12602802 is a direct replacement for several other numbers, including 89017750, 12582605, 12589463, 89017734, and 28042802.
Where is the VIN on my truck?
Your VIN can be found on a metal plate on the driver’s side of the dashboard (viewable through the windshield), on the driver’s side door jamb sticker, and on your vehicle’s registration and insurance documents.