Restore Your Van’s Reliability and Performance
Is your 1999-2002 Chevy Express or GMC Savana van suddenly running rough, refusing to start, or showing a persistent Check Engine Light? Before you start throwing expensive parts at it, the problem could be its electronic brain: the Powertrain Control Module (PCM). As a technician with over two decades of experience, I’ve seen countless vans and trucks from this era develop frustrating, intermittent issues that all trace back to a failing PCM. Heat, vibration, and age take their toll on these critical components, leading to problems that can leave you stranded.
This isn’t just a replacement part; it’s a complete solution. We take a reliable PCM and program it specifically to your vehicle’s Vehicle Identification Number (VIN). This means it arrives at your door with the latest GM factory software updates, which often correct drivability and performance flaws present in the original programming. You get a module that is ready for installation, eliminating the need for a costly trip to the dealership for programming. This is the most direct and effective way to get your workhorse back on the road and running smoothly.
A Technician’s Notebook: The Phantom Misfire
I remember a 2001 Savana 2500 that came into the shop with a random misfire code (P0300) that the owner had been chasing for months. He’d replaced plugs, wires, the distributor cap, and even the fuel injectors. The misfire was intermittent, mostly happening after the van was fully warmed up on hot days. After confirming his new parts were good, we hooked up our diagnostic scanner and monitored the PCM data streams. We noticed the injector pulse width signals would become erratic as the engine bay temperature climbed. The culprit? The original PCM was failing internally when it got hot—a classic symptom. Swapping in a properly programmed 1999-2002 Express 1500 PCM like this one solved the problem instantly. The customer was back in business without wasting any more time or money on unnecessary parts.
Is Your Vehicle Showing These Symptoms?
A failing PCM can cause a wide range of issues. If you’re experiencing any of the following, this module is the likely solution:
- ✔ Persistent Check Engine Light (CEL)
- ✔ Diagnostic Trouble Codes (DTCs) for internal module failure, such as P0601, P0604, or P0606
- ✔ Vehicle will not start or is difficult to start
- ✔ Poor or erratic engine performance and hesitation
- ✔ Decreased fuel economy
- ✔ Harsh or incorrect automatic transmission shifting
- ✔ Failure to pass an emissions inspection
A Straightforward Guide to Your PCM Swap
Installing your new PCM is a job most DIYers can handle with basic tools. Here’s a simple process to follow:
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the Old PCM: On most Express and Savana vans, the PCM is located in the engine compartment, typically on the left-hand (driver’s side) rear area. On some trucks and SUVs, it may be on the firewall or under the battery tray.
- Disconnect the Harnesses: Carefully unclip and remove the electrical wiring harnesses connected to the module. These connectors have locking tabs that need to be released before they can be pulled off.
- Remove the 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 onto the bracket and securely re-connect the wiring harnesses. Ensure they click into place.
- Reconnect Power: Re-attach the negative battery terminal.
- Perform Security Relearn (If Needed): In many cases, you may need to perform a simple security relearn procedure so the vehicle recognizes the new module. 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. Consult your vehicle’s service information for the exact procedure.
Verified Vehicle Compatibility List
This module is a direct replacement for part numbers 16263494, 16265035, 8162634940, 218-11787, and 21811787. It fits a wide range of GM trucks, vans, and SUVs. Please confirm your vehicle is listed below. Note: Some models require matching the ID number 16263494.
CHEVROLET EXPRESS 1500/2500/3500 VAN 99-02
GMC SIERRA 1500/2500/3500 PICKUP 99-00
GMC SAVANA 1500/2500/3500 VAN 99-02
CADILLAC ESCALADE 99-00
CHEVROLET TAHOE 99-00 (Classic Style)
GMC YUKON / YUKON DENALI 99-00
CHEVROLET SUBURBAN 1500/2500 99
CHEVROLET ASTRO 99-01
GMC SAFARI 99-01
CHEVROLET S10 / GMC SONOMA 98-00 (4.3L)
CHEVROLET BLAZER / GMC JIMMY 98-00
OLDSMOBILE BRAVADA 98-00
GMC ENVOY 98-00
ISUZU HOMBRE 98-00 (4.3L)
(Note: Some 1998 models require build date option ZN4. Please verify fitment.)
Frequently Asked Questions
Do I need to get this module programmed by a dealer?
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 for installation, saving you time and money.
What information do you need from me?
After you place your order, you will need to provide us with your 17-digit Vehicle Identification Number (VIN). This is crucial for us to load the correct GM software for your vehicle’s specific configuration.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM controls both engine and transmission functions. If the module is faulty, it can cause erratic shifting, delayed engagement, or other transmission issues. A new, correctly programmed PCM can resolve these communication errors.
Where is the PCM located on my 2001 Express 1500?
On the 1999-2002 Express and Savana vans, the PCM is located in the engine compartment on the driver’s side, near the firewall.
Is any other relearn procedure required after installation?
Most vehicles will require a security relearn (also known as a Passlock or VATS relearn) to allow the engine to start. This is a simple procedure you can do yourself with the ignition key. In some cases, a Crankshaft Position Variation (CASE) relearn may be needed to clear a P1336 code, which requires a capable scan tool.