If you’re dealing with frustrating and unpredictable issues in your 1998-2000 GMC Envoy, the root cause is often the very component that controls everything: the Powertrain Control Module (PCM). As an experienced technician, I’ve seen countless vehicles from this era develop baffling problems—stalling at stoplights, erratic transmission shifts, or a check engine light that just won’t go away. These aren’t signs that your truck is done for; they’re classic symptoms of a failing PCM. This module is the central nervous system of your vehicle, and when it falters, performance and reliability suffer.
We offer a dependable and straightforward solution. This isn’t just a replacement part; it’s a fully programmed Powertrain Control Module tailored specifically for your vehicle. Before we ship it, our experts flash the unit with the latest official GM software updates using the VIN you provide. This critical step ensures that your new 1998-2000 Envoy PCM communicates flawlessly with your engine, transmission, and all other onboard systems, restoring the smooth operation you expect. You get a reliable fix without the exorbitant cost and scheduling hassles of a dealership visit.
Is Your Envoy Exhibiting These Classic PCM Failure Signs?
- ✔ Persistent Check Engine Light (CEL) with communication error codes like P0601, P0605, or other U-codes.
- ✔ The engine cranks but refuses to start, or starts and immediately stalls.
- ✔ Noticeable decrease in fuel economy for no apparent reason.
- ✔ Harsh or delayed shifting from the automatic transmission.
- ✔ The vehicle randomly stalls while driving or idling.
- ✔ Communication failure with your OBD-II scan tool.
From the Diagnostic Bay: The Ghost in the Machine
A customer brought in a ’99 Jimmy, which shares the same platform and 1998-2000 Envoy PCM, with a problem that was driving him crazy. It would run perfectly fine for days, then suddenly stall at a red light and refuse to restart for 10-15 minutes. He had already replaced the fuel pump and ignition coil. When I connected my scanner, I couldn’t establish communication—a huge red flag. After letting it cool down, it connected, showing no hard codes. Experience told me this was a heat-related internal failure in the PCM. The circuit board develops micro-fractures over two decades of heat cycles. We installed one of our pre-programmed modules, and the ‘ghost’ was gone for good. It’s a textbook failure for these units.
A Straightforward Guide to Your PCM Swap
- ✔ Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait 10 minutes to ensure all systems are powered down.
- ✔ Locate the Module: On the 1998-2000 GMC Envoy, the PCM is typically found in the engine bay, on the right-hand (passenger) side, often near the firewall or inner fender.
- ✔ Disconnect the Harnesses: Carefully unlatch and remove the electrical connectors from the old PCM. Inspect the connectors for any corrosion or bent pins.
- ✔ Remove the Old PCM: Unbolt the module from its mounting bracket. Keep the hardware as you may need it for the new installation.
- ✔ Install the New Module: Mount your new, pre-programmed PCM and securely reconnect the electrical harnesses. Ensure they click into place.
- ✔ Final Steps: Reconnect the negative battery terminal. It is advisable to let the vehicle idle for 5-10 minutes to allow the computer to complete its internal self-checks and learn idle parameters.
Verified Fitment for Your GM Vehicle
This module is a direct replacement for part number 16263494 and is compatible with a wide range of GM trucks and vans. Please verify your vehicle is on the list below. Remember to provide your VIN upon checkout for correct programming.
CHEVROLET 2500 PICKUP 00 Electronic Control Module; gasoline (LH front engine compartment)
EXPRESS 1500 VAN 00 Electronic Control Module; (LH rear engine compartment)
EXPRESS 2500 VAN 00 Electronic Control Module; (LH rear engine compartment), gasoline
EXPRESS 3500 VAN 00 Electronic Control Module; (LH rear engine compartment), gasoline
SAVANA 1500 VAN 01-02 Electronic Control Module; (LH rear engine compartment), ID 16263494
ASTRO 00-01 Electronic Control Module; (LH front by battery), ID 16263494
GMC 3500 PICKUP 00 Electronic Control Module; gasoline (LH front engine compartment)
EXPRESS 2500 VAN 01-02 Electronic Control Module; (LH rear engine compartment), gasoline, ID 16263494
S10/S15/SONOMA 99-00 Electronic Control Module; (RH front engine compartment), 4.3L
SAVANA 1500 VAN 00 Electronic Control Module; (LH rear engine compartment)
ASTRO 99 Electronic Control Module; (LH front by battery), (4.3L), ID 16263494
ISUZU HOMBRE 99-00 Electronic Control Module; (RH front engine compartment), 4.3L (6 cylinder)
SAFARI (GMC) 99-01 Electronic Control Module; (LH front by battery), ID 16263494
SAVANA 3500 VAN 01-02 Electronic Control Module; (LH rear engine compartment), gasoline, ID 16263494
EXPRESS 1500 VAN 99 Electronic Control Module; (LH rear engine compartment), ID 16263494
GMC 1500 PICKUP 99 Electronic Control Module; 5.0L, (LH engine compartment), ID 16263494
BLAZER S10/JIMMY S15 98 Electronic Control Module; (RH front engine compartment), w/build date opt ZN4
GMC 1500 PICKUP 99 Electronic Control Module; 5.7L, (LH engine compartment), ID 16263494
SAVANA 3500 VAN 99 Electronic Control Module; (LH rear engine compartment), gasoline, ID 16263494
SAVANA 3500 VAN 00 Electronic Control Module; (LH rear engine compartment), gasoline
TAHOE 00 Electronic Control Module; Classic style (LH front engine compartment)
YUKON 99 Electronic Control Module; (LH engine compartment), ID 16263494
ESCALADE 99 Electronic Control Module; (LH front engine compartment), ID 16263494
ESCALADE 00 Electronic Control Module; (LH front under battery)
EXPRESS 2500 VAN 99 Electronic Control Module; (LH rear engine compartment), gasoline, ID 16263494
S10/S15/SONOMA 98 Electronic Control Module; 6-262 (4.3L), w/build date opt ZN4
YUKON 00 Electronic Control Module; (LH front under battery), Denali
BRAVADA 98 Electronic Control Module; (6-262, 4.3L), w/build date opt ZN4
CHEVROLET 3500 PICKUP 00 Electronic Control Module; gasoline (LH front engine compartment)
ENVOY 99-00 Electronic Control Module; (RH front engine compartment)
EXPRESS 1500 VAN 01-02 Electronic Control Module; (LH rear engine compartment), ID 16263494
EXPRESS 3500 VAN 99 Electronic Control Module; (LH rear engine compartment), gasoline, ID 16263494
GMC 3500 PICKUP 99 Electronic Control Module; gasoline (LH front engine compartment), ID 16263494
ISUZU HOMBRE 98 Electronic Control Module; 4.3L (6 cylinder), w/extended build date opt ZN4
SIERRA 1500 PICKUP 99-00 Electronic Control Module; (LH front under battery), 6 cylinder
SAVANA 2500 VAN 00 Electronic Control Module; (LH rear engine compartment), gasoline
SUBURBAN 1500 99 Electronic Control Module; gasoline (LH front engine compartment), ID 16263494
CHEVROLET 1500 PICKUP 99 Electronic Control Module; 5.7L, (LH engine compartment), ID 16263494
EXPRESS 3500 VAN 01-02 Electronic Control Module; (LH rear engine compartment), gasoline, ID 16263494
GMC 2500 PICKUP 00 Electronic Control Module; gasoline (LH front engine compartment)
SILVERADO 1500 PICKUP 99-00 Electronic Control Module; (LH front under battery), 6 cylinder
SUBURBAN 2500 99 Electronic Control Module; gasoline (LH front engine compartment), ID 16263494
BLAZER S10/JIMMY S15 99-00 Electronic Control Module; (RH front engine compartment)
CHEVROLET 3500 PICKUP 99 Electronic Control Module; gasoline (LH front engine compartment), ID 16263494
SAVANA 1500 VAN 99 Electronic Control Module; (LH rear engine compartment), ID 16263494
TAHOE 99 Electronic Control Module; gasoline (LH front engine compartment), ID 16263494
BRAVADA 99-00 Electronic Control Module; (RH front engine compartment)
CHEVROLET 1500 PICKUP 99 Electronic Control Module; 5.0L, (LH engine compartment), ID 16263494
SAVANA 2500 VAN 99 Electronic Control Module; (LH rear engine compartment), gasoline, ID 16263494
SAVANA 2500 VAN 01-02 Electronic Control Module; (LH rear engine compartment), gasoline, ID 16263494
ENVOY 98 Electronic Control Module; (RH front engine compartment), w/build date opt ZN4
GMC 2500 PICKUP 99 Electronic Control Module; gasoline (LH front engine compartment), ID 16263494
Frequently Asked Questions
Why do you need my VIN?
Your Vehicle Identification Number (VIN) allows us to program the module with the exact software and calibrations specific to your Envoy’s engine, transmission, and factory options. This ensures perfect compatibility and performance right out of the box.
Will I need to do any other programming after installation?
No. This module arrives ready for installation. In some cases, a security relearn procedure may be necessary, which can typically be done without special tools. Instructions are easy to find online or in your vehicle’s service manual.
What if the part number on my old module is different?
This module is a direct replacement for several part numbers, including 16265035 and 8162634940. As long as your vehicle is on our compatibility list, this module will work correctly once programmed to your VIN.
Is this a difficult part for a DIYer to replace?
Not at all. For most of the vehicles this fits, the PCM is easily accessible in the engine bay. With basic hand tools and our pre-programmed module, it’s a job most DIY enthusiasts can complete in under an hour.