Is Your GM Truck or Van Running Rough? The PCM Might Be the Culprit.
The Powertrain Control Module, or PCM, is the central brain of your vehicle’s engine and transmission. It controls everything from fuel injection and spark timing to transmission shift points and emissions equipment. When it starts to fail on your late 90s GM truck or van, it can cause a host of frustrating and difficult-to-diagnose problems. This genuine, used OEM PCM, service number 16266645, is the reliable and cost-effective solution to get your vehicle running properly again.
Unlike a generic part from a local auto parts store, this unit is professionally programmed to your vehicle’s specific Vehicle Identification Number (VIN) before it ships. This critical step ensures that the computer has the correct software and calibrations for your exact engine, transmission, and emissions options. This eliminates the need for an expensive trip to the dealership for programming, saving you time and money.
From the Diagnostic Bay
I once had a 1998 Chevy K1500 in the shop with an intermittent no-start condition that was driving the owner crazy. He had already replaced the fuel pump, ignition coil, and crank sensor based on advice from forums. The truck would run fine for days, then suddenly refuse to start. When we hooked up the scanner, we noticed the 5-volt reference signal to the sensors would occasionally drop out. Instead of a faulty sensor, the issue was a failing driver inside the original PCM. A replacement, programmed PCM like this one solved the problem instantly. It’s a reminder that the PCM itself can be the root cause of what looks like a sensor or component failure.
Diagnosing a Faulty 1999 Escalade PCM
A failing engine computer can mimic many other mechanical or electrical issues. If you’re experiencing any of the following, a faulty PCM could be the reason. Always perform proper diagnostics, but be aware of these common indicators of PCM failure.
- ✔ Persistent Check Engine Light (CEL) that won’t clear, or codes pointing to multiple unrelated sensor failures.
- ✔ Engine cranks but refuses to start, especially when intermittent.
- ✔ Rough or unstable idle, stalling, and poor engine performance.
- ✔ Noticeable decrease in fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Failure to communicate with a diagnostic scan tool.
- ✔ Failing a state emissions test due to readiness monitor issues.
The Right Part, Programmed and Ready
This PCM is a direct replacement for a wide range of 1998 and 1999 GM trucks, SUVs, and vans, including the Chevrolet Silverado, Tahoe, Suburban, Express, GMC Sierra, Yukon, Savana, and Cadillac Escalade. It is compatible with multiple service numbers, including 09355699, 16266645, 9355699, 16250279, 16258815, 09366810, and 9366810. By providing your VIN upon purchase, you guarantee that the module you receive is loaded with the latest GM-approved software for your vehicle, ensuring optimal performance and reliability. Installation is straightforward, though some vehicles may require a simple security relearn procedure (often called a VATS or Passlock relearn) which can be done without special tools.
Frequently Asked Questions
Why do I need to provide my VIN?
Your vehicle’s VIN (Vehicle Identification Number) allows us to load the exact, correct software calibration from GM for your specific engine, transmission, and options. This ensures the PCM works perfectly with your vehicle, right out of the box.
Is this part difficult to install?
Installation is typically straightforward. The PCM is usually located in the engine bay. After disconnecting the battery, you simply unplug the old module’s electrical connectors and unbolt it, then install the new one. Some vehicles may require a security relearn procedure, which takes about 30 minutes and involves cycling the ignition key. Instructions are widely available online.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of your old PCM, then yes, this part will resolve the issue. However, if the light is on due to a faulty sensor or another mechanical problem, you will still need to repair that underlying issue.
Is this a new part?
No, this is a high-quality, tested, and fully functional used OEM (Original Equipment Manufacturer) part sourced from a salvaged vehicle. This provides the reliability of a genuine GM part at a significant cost saving.
What if my original part number is not on your list?
The part numbers listed (09355699, 16266645, etc.) are the most common compatible service numbers. If your number is different, please contact us with your VIN. We can verify compatibility to ensure you get the correct module for your truck or van.