Restore Your GM Truck’s Brain and Get Back on the Road
If you’re dealing with frustrating engine problems on your 1998-2000 GMC Envoy or another compatible GM vehicle, a failing Powertrain Control Module (PCM) is often the culprit. As a technician with over two decades of experience, I’ve seen firsthand how a faulty PCM can cause a cascade of issues that seem impossible to diagnose. From a persistent Check Engine Light to poor fuel economy and sudden stalling, the symptoms can make your reliable truck feel unpredictable. This isn’t just an inconvenience; it’s a matter of reliability and safety.
This replacement PCM is the definitive solution. We take the guesswork and high dealership costs out of the equation by pre-programming this module specifically for your vehicle using your VIN. This means it arrives at your door with the latest GM software updates, ready for installation. You’re not just buying a part; you’re buying a complete, hassle-free fix that restores your engine’s performance, efficiency, and smooth operation.
Is Your GM Truck Showing These Signs of PCM Failure?
- ✔ Persistent Check Engine Light with codes like P0601, P0605, or P0606 (Internal Module Failure).
- ✔ Unexplained engine stalling or hesitation, especially when warm.
- ✔ Rough or erratic idling.
- ✔ Noticeable decrease in fuel mileage.
- ✔ Harsh or incorrect transmission shifting.
- ✔ Complete no-start condition where the engine cranks but won’t fire.
- ✔ Failure to pass an emissions or smog test.
Case Study: A Tricky Diagnosis
A customer brought in a ’99 Chevy S10 with the 4.3L V6 that had a maddening intermittent no-start condition. It would run fine for days, then refuse to start for an hour. There were no consistent trouble codes, and we’d already checked fuel pressure and spark, which were fine when it was running. After hours of chasing wires, we suspected the PCM. On these GM trucks, heat soak can cause internal solder joints in the module to fail intermittently. We swapped in one of our pre-programmed PCMs, and the problem vanished instantly. The customer called a month later to say his truck hadn’t missed a beat since. This is the kind of definitive fix this 1998-2000 Envoy PCM provides.
A Straightforward Guide to Installation
- ✔ Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post.
- ✔ Locate the PCM: On the GMC Envoy, Blazer, S10, and similar models, the PCM is typically located in the engine bay on the right-hand (passenger) side, near the firewall or fender. On Express/Savana vans, it’s often in the left-rear of the engine compartment.
- ✔ Disconnect the Module: Carefully unplug the electrical harness connectors. These usually have a locking tab or lever that needs to be released. Avoid forcing them.
- ✔ Remove the Old PCM: Unbolt the module from its mounting bracket. Keep the hardware, as you may need to reuse it.
- ✔ Install the New PCM: Mount your new, pre-programmed PCM and securely reconnect the electrical harnesses. You should hear a click as they lock into place.
- ✔ Reconnect Battery: Re-attach the negative battery terminal.
- ✔ Perform Security Relearn: Most of these GM vehicles require a simple security relearn procedure (often called the Passlock or Passkey relearn). 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. This syncs the new PCM with your vehicle’s anti-theft system.
Verified Vehicle Compatibility
This module is a direct replacement for a wide range of popular GM trucks and vans, ensuring a perfect fit and function. While it is the correct 1998-2000 Envoy PCM, it also fits many other vehicles. Please verify your part number (16263494, 16265035, etc.) or contact us with your VIN to confirm. Key compatible models include:
- ✔ 1998-2000 GMC Envoy
- ✔ 1998-2000 Chevrolet S10 / GMC Sonoma (4.3L)
- ✔ 1998-2000 Chevrolet Blazer / GMC Jimmy
- ✔ 1999-2000 Chevrolet Silverado & GMC Sierra (4.3L V6)
- ✔ 1999-2002 Chevrolet Express & GMC Savana Vans (Gasoline)
- ✔ 1999-2000 Cadillac Escalade, Chevrolet Tahoe, GMC Yukon
- ✔ And many more models listed in the detailed fitment chart.
Frequently Asked Questions
Do I need to get this module programmed?
No. The main benefit of our service is that we program the module to your vehicle’s specific VIN before we ship it. It arrives ready to install, saving you a trip to the dealership and their programming fees.
What happens after I purchase?
After you complete your purchase, you will need to send us your vehicle’s 17-digit VIN. We cannot ship the module until we receive your VIN, as the programming is essential for it to function in your truck.
Will this fix my transmission shifting issues?
In many cases, yes. The PCM controls both engine functions and automatic transmission shift points. A failing module can cause erratic shifting, delayed engagement, or getting stuck in one gear. A new, correctly programmed PCM often resolves these issues.
Is the security relearn procedure difficult?
Not at all. The standard GM relearn procedure is designed to be done without any special tools. It typically takes about 30 minutes and just involves cycling the ignition key. Instructions are widely available online for your specific model.
What part numbers is this compatible with?
This module, our part number 218-11787, is a direct replacement for several OEM part numbers, including 16263494, 16265035, and 8162634940, among others.