Restore Your Truck’s Brain and Get Back on the Road
Is your 1998-1999 GM truck or van giving you headaches? Unexplained check engine lights, stalling, rough idling, or a frustrating no-start condition can often be traced back to one component: a failing Powertrain Control Module (PCM). As a technician with over two decades of experience, I’ve seen how a faulty PCM can mimic a dozen other problems, leading to wasted time and money on unnecessary parts. This isn’t just a component; it’s the central command center for your engine and transmission. When it fails, your vehicle’s reliability is gone.
This is your direct, no-hassle solution. We are offering a genuine, used OEM 1998-1999 GMC 1500 PCM that is professionally programmed to your vehicle’s specific Vehicle Identification Number (VIN). We flash it with the latest official GM software updates, ensuring it corrects factory bugs and optimizes performance. This means you get a reliable part that’s ready for installation right out of the box, saving you a costly trip to the dealership for programming.
A Technician’s Notebook
I remember a ’99 Chevy 1500 that came into the shop on a tow truck. The owner had replaced the fuel pump, ignition coil, and spark plugs trying to solve an intermittent stalling issue that eventually became a permanent no-start. His scanner couldn’t communicate with the engine computer. After checking the power and grounds to the PCM, it was clear the module itself was the culprit. These older PCMs are tough, but heat cycles and age eventually cause internal solder joints and components to fail. We installed a VIN-programmed unit just like this one, and the truck fired right up and ran smoother than it had in years. It’s a classic fix for a problem that can be incredibly frustrating to diagnose.
Is Your Truck Showing These Signs of PCM Failure?
- ✔ Persistent Check Engine Light (CEL) that won’t clear
- ✔ Diagnostic Trouble Codes (DTCs) related to internal module failure, such as P0601, P0605, or P0606
- ✔ Complete loss of communication with your scan tool
- ✔ Engine randomly stalls, hesitates, or misfires
- ✔ Vehicle won’t start, even with a good battery and starter
- ✔ Poor fuel economy and decreased engine power
- ✔ Erratic or harsh automatic transmission shifting
- ✔ Failure to pass state emissions testing
A Straightforward Guide to Installation
Installing your programmed 1998-1999 GMC 1500 PCM is a job most DIYers can handle in under an hour with basic hand tools. This process avoids expensive dealership labor and programming fees.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the PCM: On most of these trucks and vans, the PCM is located in the engine compartment, typically on the driver’s side (LH) fender well or near the battery.
- Disconnect the Harnesses: Carefully unclip and remove the electrical connectors from the old PCM. The levers on the connectors can be stiff, so apply steady pressure. Inspect the connectors for any corrosion or damage.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket and remove it from the vehicle.
- Install the New PCM: Mount your new, pre-programmed PCM onto the bracket and securely reconnect the electrical harnesses. You should hear a click as they lock into place.
- Reconnect the Battery: Re-attach the negative battery terminal.
- Security Relearn Procedure: For many of these GM vehicles, you will need to perform a simple security relearn. Turn the key to the ‘ON’ position for 10-15 minutes, then turn it ‘OFF’ for 10 seconds. Repeat this cycle 3 times. On the final cycle, the vehicle should start. This syncs the new PCM with your vehicle’s anti-theft system.
Verified Vehicle Compatibility
This module, identified by service number 09366810 or interchange ID 9355699, is a direct replacement for a wide range of 1998-1999 GM vehicles. Please verify your part number before ordering. This part is compatible with the following models:
- Cadillac Escalade: 1999
- Chevrolet/GMC 1500, 2500, 3500 Pickups: 1998-1999 (Gasoline)
- Chevrolet/GMC Suburban 1500, 2500: 1998-1999 (Gasoline)
- Chevrolet Tahoe / GMC Yukon: 1998-1999 (Gasoline)
- Chevrolet Express / GMC Savana 1500, 2500, 3500 Vans: 1998-1999 (Gasoline)
- Chevrolet Astro / GMC Safari: 1998
- Chevrolet S10 / GMC Sonoma: 1998 (4.3L V6)
- Chevrolet Blazer / GMC Jimmy: 1998 (4.3L V6)
- Oldsmobile Bravada: 1998
- GMC Envoy: 1998
- Isuzu Hombre: 1998 (4.3L V6)
This module replaces part numbers: 09355699, 16266645, 16250279, 16258815, and 9366810.
Frequently Asked Questions
Why do you need my VIN?
Your VIN is essential. It allows us to access the specific GM database for your vehicle and program the PCM with the correct software, including engine and transmission calibrations, and any anti-theft information. This ensures the module works perfectly with your truck’s options.
Is this a new part?
No, this is a high-quality, tested used OEM part sourced from a salvaged vehicle. We inspect and verify each unit for functionality before programming and shipping. This provides an affordable and reliable alternative to a costly new part.
Do I need to do anything after installation?
In most cases, you will need to perform a security relearn procedure, which takes about 30 minutes and involves cycling the ignition key. Some models may also require a Crankshaft Variation Relearn (CASE relearn) to clear a P1336 code, which can be done with many professional-grade scan tools.
Will this fix my transmission shifting problems?
If your shifting issues are caused by the PCM, then yes. The PCM controls shift points and line pressure in the transmission. A faulty module can cause harsh shifts, delayed engagement, or slipping. A correctly programmed PCM restores proper transmission function.
What if I order the wrong part?
Please double-check the part number on your original PCM before ordering. The list of compatible vehicles is extensive. Matching the ID number (e.g., 9355699) is the best way to guarantee compatibility and a smooth installation.