Restore Peak Performance to Your GM Truck or SUV
If your 1998-2000 GMC Envoy, Chevy S10, or other compatible GM vehicle is suffering from frustrating issues like a persistent Check Engine Light, erratic shifting, or a no-start condition, the root cause is often a failing Powertrain Control Module (PCM). As the central computer of your vehicle, a faulty PCM can create a cascade of problems that are difficult to diagnose. This direct-fit replacement 1998-2000 Envoy Powertrain Control Module arrives at your door fully programmed with the latest GM software updates, tailored specifically to your vehicle’s VIN. This eliminates the need for expensive dealership visits and gets you back on the road with confidence.
Case Study: A Tricky Diagnosis
I remember a 1999 GMC Jimmy that came into my shop a few years back. The owner had already replaced the spark plugs, wires, and even the fuel pump chasing an intermittent misfire and harsh 1-2 shift. The codes were all over the place—random misfires, transmission communication errors. After checking the wiring harnesses for the third time, we hooked up our scope to the PCM outputs. We found the injector driver signals were dropping out randomly. A new, properly programmed PCM fixed everything instantly. The owner was thrilled to have his truck running smoothly again after weeks of guesswork. This is a classic example of how a failing PCM can mimic other component failures.
Is Your GM Truck or SUV Showing These Signs?
A failing PCM doesn’t always die completely. It often starts with subtle, annoying symptoms that can be misdiagnosed. If you’re experiencing any of the following, your engine computer could be the culprit:
- ✔ Persistent Check Engine Light (CEL) with codes like P0601, P0605, or U-series communication codes.
- ✔ Engine stalling, stumbling, or hesitation during acceleration.
- ✔ Rough or unpredictable idling.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ A sudden, unexplained drop in fuel economy.
- ✔ Complete no-start condition where the engine cranks but won’t fire.
- ✔ Failure to pass an emissions test.
A Straightforward Guide to Installation
Replacing your PCM is a job most DIYers can handle in their garage. Our pre-programmed module makes it a simple plug-and-play process. While locations vary slightly by model, the general steps are consistent.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait 10-15 minutes for the system to fully discharge.
- Locate the Module: On most S10/Blazer/Envoy models, the PCM is on the right-hand (passenger) side of the engine compartment. On Express/Savana vans, it’s often in the left rear of the engine bay. On full-size trucks, it’s typically on the left side or under the battery tray.
- Disconnect Connectors: Carefully unclip and remove the wiring harness connectors from the old PCM. Inspect them for any corrosion or damage.
- Remove the Old Unit: Unbolt the old PCM from its mounting bracket.
- Install the New PCM: Mount your new, pre-programmed PCM and securely re-attach the wiring harness connectors. Ensure they click into place.
- Reconnect Battery: Re-attach the negative battery terminal.
- Perform Security Relearn: In most cases, you will need to perform a simple security relearn procedure. This typically involves turning the key to the ‘ON’ position for 10-15 minutes. Consult your vehicle’s service information for the exact procedure. The vehicle will not start until this is completed.
Verified Vehicle Compatibility
This module is a direct replacement for multiple original equipment part numbers, including 16263494, 16265035, and 8162634940. It fits a wide range of GM vehicles, ensuring a perfect match. A partial fitment list includes:
- 1998-2000 GMC Envoy (RH front engine compartment)
- 1998-2000 Chevrolet S10 / GMC Sonoma (4.3L, RH front engine compartment)
- 1998-2000 Chevrolet Blazer / GMC Jimmy (RH front engine compartment)
- 1998-2000 Oldsmobile Bravada (RH front engine compartment)
- 1999-2000 Cadillac Escalade
- 1999-2000 Chevrolet Tahoe / GMC Yukon
- 1999-2002 Chevrolet Express / GMC Savana Vans (Gasoline Engines)
- 1999-2000 Chevrolet & GMC 1500/2500/3500 Pickups (Gasoline Engines)
- …and many more. Please use the fitment chart to confirm for your specific vehicle.
Choosing this pre-flashed 1998-2000 Envoy Powertrain Control Module is the most reliable and efficient way to solve complex electronic issues and restore your vehicle’s original performance and dependability.
How do I provide my VIN for programming?
How do I provide my VIN for programming?
After you complete your purchase, you will receive an email prompting you for your vehicle’s 17-digit VIN. Simply reply to that email, and our technicians will program the module with the latest GM software specific to your vehicle before shipping.
Is this module truly plug-and-play?
Yes, it is. Because we program it to your VIN, it eliminates the need for a trip to the dealership for flashing. The only additional step required after installation is a simple security relearn procedure, which does not require any special tools.
What is a security relearn?
The security relearn (also known as the Passlock or VATS relearn) syncs the new PCM to your vehicle’s anti-theft system. It’s a simple process that usually involves leaving the key in the ‘ON’ position for about 10-15 minutes. Your vehicle will not start until this is done.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM controls engine performance and transmission shift points. If the module is failing, it can send incorrect signals, leading to hard shifts, slipping, or delayed engagement. A new, correctly programmed PCM often resolves these communication-based transmission issues.