Is Your GM Truck or Van Running Rough?
If you’re dealing with a persistent check engine light, erratic engine behavior, stalling, or a no-start condition in your 1998 or 1999 GM vehicle, a failing Powertrain Control Module (PCM) is often the culprit. Over two decades in the shop, I’ve seen hundreds of these specific PCMs fail due to heat cycles and age, leading to frustrating and hard-to-diagnose problems. This isn’t just a part; it’s the solution to getting your reliable workhorse back on the road.
This is a genuine, used OEM Electronic Control Module, service number 9355699, that has been meticulously tested and is ready for a new life in your vehicle. Before we ship it, our technicians will program it with the latest GM software updates using the Vehicle Identification Number (VIN) you provide. This ensures it communicates perfectly with your truck or van’s specific systems, restoring factory performance and efficiency.
From the Shop Floor: A Real-World Scenario
“A customer’s ’99 Suburban came in last week with a random misfire (P0300) and a harsh 1-2 shift that two other shops couldn’t solve. They had already replaced plugs, wires, and even the transmission fluid. After confirming good power and grounds at the PCM connectors, we suspected the module itself. The internal drivers that control the ignition and transmission solenoids can weaken over time. We installed one of our VIN-programmed PCMs, performed the security relearn, and the truck ran and shifted like it just left the showroom. It’s a fix I’ve performed countless times on these GMT400 platform vehicles.”
Why Choose Our Programmed PCM?
- ✔ VIN-Specific Programming: We flash the module with your vehicle’s exact VIN and the newest official GM calibrations for optimal engine and transmission function.
- ✔ Solve Common Issues: A direct solution for symptoms like random misfires, poor fuel economy, harsh shifting, and intermittent stalling.
- ✔ Broad Compatibility: This unit replaces a wide range of part numbers, including 09355699, 16266645, 16250279, 16258815, and 09366810.
- ✔ Cost-Effective Repair: Get a reliable, programmed computer without the high cost of a new part from the dealership.
Easy Installation for Your 1998-1999 Chevrolet 2500 PCM
While professional installation is always recommended, this is a straightforward job for a confident DIYer. The most critical part is performing the security relearn procedure after installation.
- Safety First: Disconnect the negative terminal from your vehicle’s battery.
- Locate the PCM: On most trucks and SUVs like the Chevrolet 2500, Tahoe, and Suburban, the PCM is located in the engine compartment on the driver’s side, near the fender. On vans like the Express and Savana, it’s often in the LH rear of the engine compartment.
- Disconnect Connectors: Carefully unclip and remove all wiring harness connectors from the old module. Inspect the pins for any corrosion or damage.
- Swap the Modules: Unbolt and remove the old PCM. Mount the replacement module securely in its place.
- Reconnect Everything: Firmly plug the wiring harnesses back into the new PCM and reconnect the negative battery terminal.
- Perform Security Relearn: This step is crucial. Your vehicle will not start until this is done. Turn the key to the ‘ON’ position (without starting) for 10-15 minutes, or until the ‘Security’ light turns off. Turn the key ‘OFF’ for 30 seconds. Repeat this cycle two more times (three cycles total). The vehicle should now start and run.
Expert Pro Tip: Connector Health is Key
Before plugging in your new PCM, take a moment to spray the vehicle’s harness connectors with a quality electronics cleaner. Use a small, soft brush (like a toothbrush) to gently scrub away any dirt or faint corrosion on the pins. A clean, solid connection is vital for preventing voltage drops and ensuring the computer receives accurate data from all sensors.
Please provide your vehicle’s 17-digit VIN in the notes at checkout or send us a message after your purchase. We cannot ship your part until we have this information to complete the programming.