Restore Peak Performance to Your GM Truck or Van
Is your 1998-1999 Chevrolet Express 1500 van running rough, stalling unexpectedly, or showing a persistent check engine light? A failing Powertrain Control Module (PCM) is often the culprit, acting like a confused brain for your vehicle’s engine and transmission. In my 20+ years of diagnostics, I’ve seen firsthand how a faulty PCM can cause a cascade of frustrating issues. This isn’t just an inconvenience; it affects your vehicle’s reliability, fuel economy, and safety. This replacement PCM is the straightforward, reliable solution to get your workhorse back in top condition.
This is a quality, tested, used OEM Powertrain Control Module that has been meticulously inspected. The real value lies in our service: before this module ships, we program it specifically to your vehicle using your VIN. This means it arrives loaded with the latest GM software updates, ready for installation right out of the box. You get to skip the expensive trip to the dealership and the hassle of coordinating programming. It’s the smart, efficient fix for both professional mechanics and DIY enthusiasts.
Case Study: A Tricky Diagnosis
A customer brought in a ’99 Suburban with an intermittent no-start and random stalling that no one could figure out. It threw no consistent codes, just a random misfire now and then. We checked fuel pressure, spark, and sensors—all were fine. On a hunch, I tapped the PCM housing while the engine was idling, and it immediately stalled. The culprit was an internal connection failure in the original PCM. We replaced it with a pre-programmed module just like this one, and the customer was back on the road the same day, problem solved. These symptoms can be elusive, but often lead back to the vehicle’s central computer.
Is Your Vehicle Showing These Symptoms?
- ✔ Check Engine Light is on with codes like P0601, P0605, or P0606 (Internal Module Failure).
- ✔ The engine cranks but refuses to start.
- ✔ Rough idling, stalling, or hesitation during acceleration.
- ✔ Noticeably poor fuel mileage.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Failure to pass an emissions or smog test.
A Straightforward Guide to Installation
- ✔ Safety First: Always disconnect the negative terminal from your vehicle’s battery before beginning work.
- ✔ Locate the PCM: On most of these GM vans and trucks, the PCM is located in the engine compartment, typically on the driver’s side fender well or firewall.
- ✔ Disconnect Connectors: Carefully unclip the wiring harness connectors from the old PCM. These connectors have locking tabs that need to be released. Avoid pulling on the wires themselves.
- ✔ Remove the Old Module: Unbolt the old PCM from its mounting bracket and remove it from the vehicle.
- ✔ Install the New Module: Mount your new, pre-programmed PCM onto the bracket and securely fasten the bolts.
- ✔ Reconnect Everything: Firmly plug the wiring harnesses into the new PCM until they click into place. Reconnect the negative battery terminal.
- ✔ Final Step: In some cases, a security relearn procedure may be necessary, which can typically be done without special tools. Instructions are readily available online for your specific model.
Verified Vehicle Compatibility
This PCM, service number 16266645, is a direct replacement for multiple part numbers, including 09355699, 16250279, 16258815, and 09366810. It is guaranteed to fit a wide range of GM trucks and vans from 1998-1999 that require the hardware ID 9355699. Please verify the part number on your current module to ensure compatibility. Key models include:
- ✔ 1998-1999 Chevrolet & GMC C/K 1500, 2500, 3500 Pickups (Gasoline)
- ✔ 1998-1999 Chevrolet Express & GMC Savana 1500, 2500, 3500 Vans (Gasoline)
- ✔ 1998-1999 Chevrolet Suburban & GMC Yukon / Yukon XL (Gasoline)
- ✔ 1998-1999 Chevrolet Tahoe
- ✔ 1999 Cadillac Escalade
- ✔ 1998 Chevrolet Astro & GMC Safari
- ✔ 1998 Chevrolet S10, GMC Sonoma, Isuzu Hombre (4.3L V6)
- ✔ 1998 Chevrolet Blazer & GMC Jimmy (4.3L V6)
- ✔ 1998 Oldsmobile Bravada & GMC Envoy (4.3L V6)
Frequently Asked Questions
Do I need to do anything after I buy it?
Yes. After your purchase, you MUST send us your vehicle’s 17-digit VIN. We cannot program and ship the module without it. This ensures the PCM works correctly with your vehicle’s specific options.
Is this a plug-and-play part?
Yes, for over 95% of vehicles. Because we program it to your VIN, it should work immediately after installation. A very small number of vehicles may require a simple key security relearn procedure, which does not require a mechanic.
Is this a new part?
No, this is a high-quality, tested used OEM part sourced from a salvaged vehicle. This provides OEM reliability at a fraction of the cost of a new module from a dealer.
What if my part number is slightly different?
This module is a direct replacement for several part numbers, including 09355699, 16250279, and more as listed above. As long as your module matches one of these numbers, this part will work for you.
Where is the PCM located on my 1999 Express Van?
On the 1998-1999 Express and Savana vans, the PCM is typically located in the engine compartment, on the left-hand (driver’s side) rear portion of the engine bay.