Is Your GM Truck or Van Running Rough? The Problem Might Be Its Brain.
If your late-90s Chevy or GMC is suffering from baffling issues like harsh shifting, a persistent check engine light, stalling, or a complete no-start condition, the culprit is often the Powertrain Control Module (PCM). After 20+ years on the road, the original electronics in these workhorses can fail, leading to frustrating and costly diagnostic dead ends. I’ve seen it hundreds of times in my shop: a customer comes in thinking they need a new transmission, but the real issue is a faulty PCM sending incorrect signals.
This isn’t just a replacement part; it’s a direct solution. We offer a reliable, tested, and used OEM PCM that is professionally programmed to your vehicle’s specific Vehicle Identification Number (VIN) before it ships. This means it arrives ready for a straightforward installation, loaded with the latest GM factory software to correct common drivability issues and optimize performance.
My Real-World Experience
“A customer’s 1999 Suburban came in last week with these exact symptoms: it wouldn’t shift out of first gear and the speedometer was dead. The owner had already replaced the vehicle speed sensor twice with no luck. After a quick scan, I suspected the PCM. We plugged in one of our pre-programmed modules, and within 15 minutes, the truck was shifting perfectly and all gauges were working. It’s a classic failure on these models, and a new PCM is often the simple fix that mechanics overlook.”
Common Symptoms of a Failing GM PCM:
- โ Check Engine Light (CEL) with various communication or sensor codes
- โ Harsh or erratic automatic transmission shifting
- โ Engine stalling, stumbling, or refusing to start
- โ Poor fuel economy and loss of power
- โ Gauges on the instrument cluster not working correctly
- โ Vehicle’s security system preventing it from starting
Why Choose This 1998-1999 Express 1500 PCM?
This module is the smart, affordable way to get your vehicle back to factory-spec operation. By providing us with your VIN, you bypass the expensive trip to a dealership for programming. We handle the complex part, so you can handle the simple installation.
- โ VIN Programmed: Arrives ready to install with software matched to your exact vehicle.
- โ Latest GM Updates: Flashed with the newest software to fix original factory bugs.
- โ Cost-Effective: A high-quality, tested used OEM part at a fraction of the cost of a new unit.
- โ Broad Compatibility: This unit, identified by service number 9355699, fits a wide range of GM trucks, vans, and SUVs from this era.
Plug-and-Play Installation: No Dealer Visit Required
Installing your new PCM is a job most DIYers can handle in under 30 minutes with basic tools. Follow these steps to get back on the road:
- Safety First: Disconnect the negative terminal from your vehicle’s battery.
- Locate the PCM: On most of these GM trucks and vans (like the Express, Savana, C/K Pickup, Tahoe, and Suburban), the PCM is located in the engine compartment on the driver’s side, often near the fender or firewall. It’s a metal box with several large multi-pin connectors.
- Disconnect the Old Unit: Carefully unplug the wiring harness connectors. They have locking tabs that need to be released. Then, unbolt the module from its mounting bracket.
- Install the New PCM: Bolt the new, pre-programmed PCM into place. Firmly reconnect the wiring harnesses, ensuring they click securely into place. Pro Tip: Before connecting, inspect the harness pins for any green or white corrosion. Clean them carefully with a small brush and electrical contact cleaner if needed.
- Reconnect Power: Reattach the negative battery terminal.
- Security Relearn (If Necessary): In some cases, you may need to perform a simple security relearn procedure. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times. Your vehicle’s manual will have the specific instructions.
Part Number Compatibility
This module is a direct replacement for several part numbers. To ensure a perfect match, verify your original module has one of the following service numbers printed on the label: 09355699, 16266645, 9355699, 16250279, 16258815, or 09366810.