Is Your GM Truck or Van Running Rough?
If your 1998-1999 GMC 1500, Chevrolet 1500, Tahoe, or Suburban is experiencing frustrating issues like stalling, erratic shifting, a persistent check engine light, or even a no-start condition, the problem may lie with a failing Powertrain Control Module (PCM). As the central computer for your vehicle’s engine and transmission, a faulty PCM can cause a wide range of performance problems, leaving you stranded and facing a costly repair bill from the dealership. Don’t let a bad computer sideline your reliable GM truck.
The Brain of Your Operation: The 1998-1999 GMC 1500 PCM
The PCM is the electronic brain that manages everything from fuel injection and spark timing to transmission shift points and emissions controls. When it begins to fail, the signals it sends to critical components become unreliable, leading to the symptoms you’re experiencing. This isn’t just an inconvenience; it can affect your vehicle’s safety, fuel economy, and longevity. Replacing it is often the only way to restore your truck’s original performance and dependability.
From the Diagnostic Bay
We had a ’99 Chevy Tahoe come into the shop that was driving the owner crazy. It would run perfectly for days, then suddenly die at a stoplight and refuse to restart for 20 minutes. There were no consistent trouble codes, just a random U-code for lost communication every now and then. We checked grounds, wiring, and sensors, but everything looked solid. On a hunch, we swapped in a known-good, programmed PCM. The problem vanished instantly. The original module had an internal hairline fracture that would separate when it got hot, cutting off communication. A pre-programmed replacement like this one was the simple, effective fix that got the owner back on the road with confidence.
Symptoms of a Failing Powertrain Control Module
- ✔ Check Engine Light: Your check engine light is on, and you may have trouble codes related to module communication (U-codes) or multiple, unrelated sensor faults.
- ✔ Engine Stalling: The engine may stall intermittently, especially when warm, or die unexpectedly while driving.
- ✔ No-Start Condition: The engine cranks but will not start, often due to a lack of spark or fuel injector pulse commanded by the PCM.
- ✔ Poor Performance & Fuel Economy: You may notice a significant drop in power, hesitation during acceleration, and a noticeable decrease in miles per gallon.
- ✔ Erratic Shifting: The automatic transmission may shift harshly, slip between gears, or get stuck in one gear (limp mode).
- ✔ Failed Emissions Test: A faulty PCM can prevent the emissions system from operating correctly, leading to an automatic failure at the testing station.
A Simple, Programmed Solution
This isn’t just a replacement part; it’s a complete, ready-to-install solution. This genuine used OEM PCM is sourced from a salvaged vehicle and is guaranteed to perform to factory specifications. The critical difference is our service: we flash the module with the latest GM software updates and program it specifically to your vehicle’s unique Vehicle Identification Number (VIN) before it ships. This means you receive a true plug-and-play component. No expensive trips to the dealer for programming are required. Simply install the module, and you’re ready to go.
Guaranteed Compatibility
This electronic control module is a direct replacement for several part numbers, ensuring a perfect fit and function for a wide range of GM vehicles. Please verify that your vehicle is on the list below and that the part number matches one of the following:
Service Part Numbers: 09355699, 16266645, 9355699, 16250279, 16258815, 09366810, 9366810
This unit is a confirmed fit for the following vehicles, among others:
- 1998-1999 Chevrolet & GMC 1500/2500/3500 Pickups (Gasoline)
- 1998-1999 Chevrolet Tahoe & GMC Yukon (Gasoline)
- 1998-1999 Chevrolet & GMC Suburban 1500/2500 (Gasoline)
- 1998-1999 Chevrolet Express & GMC Savana 1500/2500/3500 Vans (Gasoline)
- 1999 Cadillac Escalade
- 1998 Chevrolet Astro & GMC Safari
- 1998 S10/S15/Sonoma, Blazer S10/Jimmy S15, Bravada, Envoy, Isuzu Hombre (4.3L V6)
Note: It is crucial to match your vehicle’s options and original module ID (9355699) to ensure compatibility.
Frequently Asked Questions
Do I need to get this PCM programmed?
No. The main benefit of our service is that we program the module for you before we ship it. Simply provide your vehicle’s VIN during or after checkout, and it will arrive ready to install.
What is a VIN flash?
A VIN flash is the process of loading your truck’s specific software and operating parameters onto the module using your 17-digit Vehicle Identification Number. This ensures the PCM communicates correctly with your engine, transmission, and all other vehicle systems.
Where is the PCM located on my 1999 GMC 1500?
On most GMT400 platform trucks like the 1998-1999 GMC 1500, the PCM is located in the engine compartment, typically on the driver’s side near the fender or firewall, housed in a black plastic bracket.
Is this a new part?
This is a high-quality, tested, and fully functional used OEM part recovered from a salvaged vehicle. This ensures you get the original factory reliability without the high cost of a new-old-stock part.
What happens if I don’t provide my VIN?
We cannot ship the module without your VIN. The programming is essential for the part to function in your vehicle. We will hold your order and contact you to get the necessary information.
Will this fix my check engine light?
If the check engine light and associated codes are a direct result of a failing PCM, then yes, this part will resolve the issue. However, it is essential to have your vehicle properly diagnosed to rule out other potential causes like faulty sensors or wiring.