Is your 1998 or 1999 Chevy or GMC truck running rough, stalling, or refusing to start? Are you battling a persistent Check Engine Light with confusing error codes? The Powertrain Control Module (PCM), the electronic brain of your vehicle, is often the source of these frustrating and hard-to-diagnose issues. This genuine used PCM, part number 09366810, is the reliable and cost-effective solution to restore your truck’s performance and get you back on the road with confidence.
The PCM is responsible for managing critical engine and transmission functions, including fuel injection, ignition timing, emissions systems, and automatic transmission shift points. When it begins to fail, it can cause a cascade of problems that can mimic other component failures, leading to wasted time and money on incorrect repairs. Replacing a faulty module with a correctly programmed unit is essential for proper vehicle operation.
From the Diagnostic Bay
We had a ’99 Suburban come into the shop with a complaint of intermittent stalling. It would run fine for days, then suddenly die at a stoplight and refuse to restart for 20 minutes. The owner had already replaced the fuel pump and ignition coil based on advice from forums, but the problem persisted. After hooking up our scanner, we noticed the live data feed from the PCM would completely drop out right before it stalled. There were no specific codes, just a loss of communication. We swapped in a known-good, programmed PCM, and the truck ran perfectly. The original module had an internal fault that only showed up when it got hot, a classic symptom of PCM failure in these GMT400 trucks.
Diagnosing a Faulty 1998-1999 Chevy 1500 PCM
A failing PCM can manifest in various ways. If your truck is experiencing any of the following symptoms, a faulty engine computer could be the culprit. Look out for these common warning signs:
- ✔ Check Engine Light: The light is on, often with communication-related codes (U-codes) or multiple, seemingly unrelated sensor codes.
- ✔ No-Start or Hard-Starting: The engine cranks but won’t start, or takes an excessively long time to fire up, either hot or cold.
- ✔ Rough Idle and Stalling: The engine idles erratically, shakes, or stalls unexpectedly while driving or at a stop.
- ✔ Poor Fuel Economy: A sudden and unexplained drop in your truck’s gas mileage can indicate the PCM is not managing the fuel mixture correctly.
- ✔ Failed Emissions Test: Inability to pass a smog check is a strong indicator of an engine management problem.
- ✔ Erratic Transmission Shifting: Harsh shifts, delayed engagement, or getting stuck in a gear can be caused by the PCM, which controls the transmission.
- ✔ Intermittent Issues: Problems that appear and disappear, often related to engine temperature, are a hallmark of a failing electronic module.
The Right Part, Programmed for Your Truck
This isn’t just a part in a box. This is a complete solution. We take a genuine, used OEM PCM and program it specifically to your vehicle’s Vehicle Identification Number (VIN). This critical step ensures that the module has the correct software and calibrations for your truck’s specific engine, transmission, and options. We install the latest GM-released software updates, which can resolve factory bugs and improve performance and drivability. By providing us with your VIN upon purchase, you receive a module that is ready for a straightforward installation.
This module is a direct replacement for multiple part numbers, including 09355699, 16266645, 16250279, 16258815, and 09366810. It fits a wide range of 1998-1999 GM trucks, vans, and SUVs, such as the Chevrolet Silverado, Tahoe, Suburban, Express, GMC Sierra, Yukon, Savana, and Cadillac Escalade. Please verify the part number on your existing module or consult the detailed fitment list to ensure compatibility.
Frequently Asked Questions
Do I need to program this PCM?
No. We handle the programming for you before shipping. Simply provide your vehicle’s VIN at checkout, and we will flash the module with the correct GM software for your specific truck.
Is this a new part?
This is a high-quality, tested, genuine used part sourced from a salvaged vehicle. This provides OEM reliability at a fraction of the cost of a new module.
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 correctly in your vehicle. We will contact you after your purchase to obtain the VIN if it was not provided.
Will I need to do anything after installing the PCM?
In most cases, you may need to perform a security relearn procedure, also known as a VATS or Passlock relearn. This is a simple procedure that typically involves turning the key on and off in a specific sequence and can be done without special tools. Instructions are widely available online for your specific model.
How do I find the part number on my old computer?
The part number is printed on a sticker on the case of your existing PCM. On most 1998-1999 GM trucks, it’s located in the engine compartment, typically on the driver’s side fender.