Restore Your Truck’s Brain and Get Back on the Road
Is your Chevrolet Avalanche or GM truck acting up? Dealing with a persistent Check Engine Light, rough idling, stalling, or unpredictable transmission shifts can be incredibly frustrating. As a mechanic with over two decades of experience under the hood, I’ve seen these symptoms countless times. Often, the root cause isn’t a faulty sensor or a bad wire; it’s the Powertrain Control Module (PCM)—the central computer of your vehicle.
This isn’t just any replacement part. This is a fully programmed, ready-to-install solution for your vehicle. We take the guesswork and the expensive trip to the dealership out of the equation. Simply provide us with your vehicle’s VIN (Vehicle Identification Number) at checkout, and our technicians will flash this module with the latest, most stable software directly from GM. This ensures your engine and transmission operate exactly as the manufacturer intended, restoring lost power, fuel efficiency, and reliability. This is the definitive fix for a failing 2003-2006 Avalanche 1500 PCM and many other GM models.
From the Diagnostic Bay
I remember a 2005 Silverado 2500 that came into my shop. The owner had spent a fortune chasing ghosts. He’d replaced the throttle body, MAF sensor, and even a few oxygen sensors trying to fix a nagging P0606 (PCM Processor Fault) code and intermittent stalling. The truck would run fine for days, then suddenly die at a stoplight. After confirming all sensor inputs were good, we focused on the PCM. We installed a VIN-programmed module just like this one. The change was immediate. The codes vanished, the idle smoothed out, and the owner called a week later, thrilled that his truck was finally dependable again. It’s a classic case of symptoms pointing everywhere but the real culprit: the main computer.
Is Your Truck Showing These Symptoms?
A failing PCM can cause a wide range of issues that are often misdiagnosed. If you’re experiencing any of the following, your engine computer is a likely suspect:
- ✔ Check Engine Light is on with communication codes (like U0100) or internal processor codes (P0601, P0606).
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained drop in fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Engine stalling, stuttering, or misfiring.
- ✔ Communication issues with your diagnostic scan tool.
A Straightforward Guide to Installation
Replacing your 2003-2006 Avalanche 1500 PCM is a job most DIYers can handle with basic tools. Because we program it beforehand, you skip the most complicated step. Follow this general guide for a successful installation.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait at least 10 minutes for the system to discharge completely.
- Locate the PCM: On most compatible trucks and SUVs, the PCM is found in the engine bay on the driver’s side, often under or near the battery tray and air filter box.
- Disconnect the Connectors: Carefully release the locking tabs on the wiring harness connectors and pull them straight out from the module. Never force them. Inspect the pins for any corrosion or damage.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket. It’s typically held in by a few bolts (commonly 10mm or 13mm).
- Install the New Module: Bolt your new, pre-programmed PCM into the bracket. Reconnect the wiring harnesses, making sure they click securely into place.
- Reconnect the Battery: Reattach the negative battery terminal.
- Perform Security Relearn: You will need to perform a simple security relearn procedure (often called a Passlock or VATS relearn) so the vehicle recognizes the new PCM. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times before starting the engine. Instructions are readily available online for your specific model.
Verified Vehicle Compatibility
This module, part number 89017750, is a direct replacement for a wide range of GM trucks and SUVs. It is also compatible with service numbers 12582605, 12589463, 12602802, 89017734, and 28042802. Please verify your vehicle is on the list below. Some 2004 models require matching the ID number 12602802.
- Avalanche 1500 (2003-2006)
- Cadillac Escalade, ESV, EXT (2003-2006)
- Chevrolet Silverado 1500, 2500, 3500 (2003-2007 Classic)
- Chevrolet Suburban 1500, 2500 (2003-2006)
- Chevrolet Tahoe (2003-2006)
- Chevrolet SSR (2003)
- GMC Sierra 1500, 2500, 3500 (2003-2007 Classic)
- GMC Sierra Denali (2003-2007 Classic)
- GMC Yukon & Yukon XL 1500/2500 (2003-2006)
- Hummer H2 (2003-2007)
- Isuzu Ascender (2003, 5.3L)
- GMC Envoy XL (2003, 5.3L)
- Chevrolet Trailblazer EXT (2003, 5.3L)
Frequently Asked Questions
Frequently Asked Questions
Why do you need my VIN?
Your VIN is essential. It allows us to program the PCM with the exact software calibration for your vehicle’s specific engine, transmission, and options. This ensures perfect compatibility and performance, just like a new module from the factory.
Is this a simple plug-and-play part?
Almost. The module is pre-programmed, which handles the most difficult part. After physical installation, you will need to perform a security relearn procedure. This is a simple process that syncs the new PCM to your vehicle’s anti-theft system and does not require special tools.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of your original PCM (e.g., codes P0601, P0606, U0100), then yes, this part is the correct fix. However, if the light is on due to a bad sensor or other system fault, you must fix that underlying issue first.
How do I find my original part number?
The part number is printed on a sticker on the case of your current PCM. You can match it to 89017750 or any of the compatible service numbers listed to confirm fitment.
What if I have a 2007 model?
This part fits 2007 ‘Classic’ body style trucks (the ones with the creased door skin, looking like the 2006 models), but not the new body style that was also introduced in 2007.