Is Your GM Truck or Van Running Rough?
If your 1998-1999 Chevrolet, GMC, or Cadillac is experiencing perplexing issues like a persistent Check Engine Light, erratic shifting, a no-start condition, or a sudden drop in fuel economy, the culprit is often the very brain of your vehicle: the Powertrain Control Module (PCM). This essential component manages everything from fuel injection and ignition timing to transmission shift points. When it fails, it can cause a cascade of problems that can be difficult to diagnose and leave you stranded.
From the Diagnostic Bay
I once had a ’99 Suburban towed in that had stumped two other shops. The owner had replaced the fuel pump, plugs, wires, and even the distributor, but it still wouldn’t start consistently. It would crank but never fire. We hooked up our scan tool and couldn’t communicate with the PCM at all. A quick check of the PCM’s power and ground circuits confirmed they were good. The module itself was dead. We installed a VIN-programmed PCM just like this one, performed the security relearn procedure, and the truck fired up on the first try. The owner was thrilled to have his reliable workhorse back without throwing any more unnecessary parts at it.
Symptoms of a Failing Powertrain Control Module
- ✔ Persistent Check Engine Light (CEL) with various trouble codes, especially communication-related codes (U-codes).
- ✔ Engine stalling, misfiring, or running rough at idle.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Complete no-start condition where the engine cranks but won’t fire.
- ✔ Noticeable decrease in fuel efficiency.
- ✔ Failure to pass an emissions test.
- ✔ Intermittent electrical issues affecting gauges or other systems.
A Direct-Fit, Programmed Solution
Don’t let a faulty computer keep your truck off the road. This is a genuine, used Powertrain Control Module (service number 09355699) that serves as a direct replacement for a wide range of 1998-1999 GM trucks and vans. The most critical part of the replacement process is the programming, and we handle that for you. Before we ship the part, our technicians will flash it with the latest official GM software calibration specifically for your vehicle’s VIN. This ensures that it communicates perfectly with your engine, transmission, and all other onboard systems, restoring the original performance and reliability you depend on.
Why Choose Our Pre-Programmed 1998-1999 Chevrolet PCM?
This isn’t just a part; it’s a complete solution. By providing us with your VIN at checkout, you eliminate the need for expensive trips to the dealership for programming. The module arrives at your door ready for installation. After installation, you will likely need to perform a simple security relearn procedure (often called a Passlock or Passkey relearn), which can typically be done in your driveway without any special tools. This process syncs the new PCM with your vehicle’s anti-theft system. This module is a cost-effective way to solve complex electronic issues and get your vehicle running correctly again.
This unit is compatible with multiple part numbers, including: 16266645, 9355699, 16250279, 16258815, 09366810, and 9366810. Please verify your part number and consult the extensive fitment list to ensure compatibility.
Frequently Asked Questions
Do I need to send you my old computer?
No, there is no core charge or need to send in your old module. This is an outright purchase of a quality used and programmed PCM.
What is the VIN programming process?
After you place your order, you provide us with your vehicle’s 17-digit VIN. Our technicians use professional-grade equipment and official GM software to load the exact calibration file for your specific vehicle onto this PCM. This ensures it works correctly with your engine, transmission, and options.
What is the security relearn procedure?
Most GM vehicles from this era have an anti-theft system (Passlock/Passkey) that needs to be synchronized with the new PCM. This is typically a simple procedure involving turning the key to the ‘ON’ position for 10-15 minutes, then ‘OFF’, and repeating the cycle three times. We can provide general instructions, but the exact procedure can vary slightly by model.
Is this a plug-and-play part?
It is as close as it gets. Because we program it to your VIN, it eliminates the most difficult step. You will still need to physically install the module and perform the security relearn procedure. In some very specific cases, a Crankshaft Variation Relearn (CASE Relearn) may be needed with a scan tool for optimal performance, but the vehicle will typically run and drive without it.
How do I find my PCM part number?
Your original PCM is usually located in the engine bay, often on the driver’s side fender or near the battery. The part number is printed on a sticker on the module itself. It will be a large 8-digit number, such as 09355699.