Restore Your GM Truck’s Performance and Reliability
Is your 1999 Cadillac Escalade, Chevy Tahoe, or GMC Yukon acting possessed? Unexplained stalling, hard starting, erratic shifting, or a check engine light that won’t quit can be incredibly frustrating. In my 20+ years of hands-on diagnostics, I’ve seen countless owners and even professional shops chase their tails, replacing perfectly good sensors and components, when the real culprit was a failing Powertrain Control Module (PCM). This isn’t just a part; it’s the brain of your engine, and when it malfunctions, it creates chaos.
This isn’t just any replacement computer. This is a thoroughly tested, reliable used PCM that we program specifically to your vehicle’s Vehicle Identification Number (VIN) before it ships. This critical step ensures compatibility and loads the latest GM software updates, resolving old bugs and optimizing performance. By providing your VIN at checkout, you get a module that’s ready for a straightforward installation, saving you a costly trip to the dealership and the hassle of finding a shop with the right programming equipment. This is the smart, effective solution to get your trusted truck or SUV back on the road.
Case Study: The Ghost in the Machine
A customer brought in a ’99 Suburban 1500 with a classic intermittent no-start condition. They had already replaced the fuel pump, crank sensor, and ignition coil based on advice from forums. The truck would run fine for days, then refuse to start. When I connected my scanner, I found a P0601 ‘Internal Control Module Memory Check Sum Error’ code stored. This code is a direct indictment of the PCM itself. The internal processor was failing intermittently, especially during temperature changes. We installed a VIN-programmed PCM just like this one, performed the security relearn, and the truck has been starting reliably ever since. It saved the customer from more guesswork and unnecessary parts expenses.
Is Your GM Truck or SUV Showing These Signs?
A failing PCM can manifest in various ways that often mimic other component failures. If you’re experiencing any of the following, your engine computer could be the root cause:
- ✔ Check Engine Light is on with codes like P0601, P0604, or P0606.
- ✔ The engine cranks but refuses to start.
- ✔ Intermittent stalling, especially when warm or at idle.
- ✔ Noticeably poor fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Communication errors with diagnostic scan tools.
- ✔ The anti-theft or security light stays on.
A Straightforward Guide to Installation
Installing your programmed 1999 Escalade PCM is a job most DIYers can handle in under an hour. The key is the security relearn procedure, which pairs the new module to your vehicle’s anti-theft system.
- Safety First: Disconnect the negative terminal from your vehicle’s battery.
- Locate the PCM: On most of these vehicles, the PCM is located in the engine compartment, typically on the driver’s side fender.
- Disconnect & Remove: Carefully unplug the color-coded wiring harness connectors. Use a screwdriver to gently pry the locking tabs if needed. Then, unbolt the module from its bracket.
- Install the New PCM: Bolt the new, programmed PCM into the bracket and securely reconnect the wiring harnesses. Ensure they click into place.
- Reconnect Battery: Re-attach the negative battery terminal.
- Perform Security Relearn (CRITICAL): This step is essential. Put the key in the ignition and turn it to the ‘ON’ position (don’t start the engine). Attempt to start the engine; it will crank but not fire. Leave the key in the ‘ON’ position for 10-12 minutes, or until the ‘Security’ light on the dash stops flashing and turns off.
- Complete the Cycle: Turn the key to ‘OFF’ for 10 seconds. Repeat the previous two steps two more times for a total of three 10-minute cycles. On the fourth attempt, the vehicle should start and run normally.
Verified Fitment for Your GM Truck or SUV
This module is a direct replacement for units with service numbers 09355699, 16266645, 9355699, 16250279, 16258815, 09366810, or 9366810. It is confirmed to fit a wide range of popular 1998 and 1999 GM vehicles, including:
- ✔ Cadillac Escalade (1999)
- ✔ Chevrolet & GMC Pickups (1500, 2500, 3500)
- ✔ Chevrolet Tahoe & GMC Yukon
- ✔ Chevrolet & GMC Suburban
- ✔ Chevrolet Express & GMC Savana Vans (1500, 2500, 3500)
- ✔ Chevrolet Astro & GMC Safari Vans
- ✔ Chevrolet S10 Blazer & GMC S15 Jimmy
- ✔ Oldsmobile Bravada, GMC Envoy, Isuzu Hombre
Please ensure your vehicle is listed and provide your VIN upon purchase for correct programming. This is the most reliable way to guarantee a perfect match for your specific 1999 Escalade PCM or other compatible vehicle.
Frequently Asked Questions
Frequently Asked Questions
Why do you need my VIN?
Your Vehicle Identification Number (VIN) allows us to program the PCM with the exact software and calibrations your vehicle had when it left the factory, plus any subsequent GM updates. This ensures proper engine, transmission, and emissions system operation.
Is this part difficult to install?
The physical swap is simple, requiring only basic hand tools. The most important part is the 30-minute security relearn procedure, which requires no tools at all—just patience. Our guide above walks you through it step-by-step.
Is this a new part?
No, this is a high-quality, tested used part sourced from a salvaged vehicle. This provides a reliable and cost-effective alternative to a new dealership part, and every unit is verified to be fully functional before programming and shipping.
What if my original part number isn’t 16266645?
This module is a direct replacement for several part numbers, including 09355699, 16250279, and others listed above. As long as your vehicle model and year are on our compatibility list, this programmed module will work for you.
Will this fix my check engine light?
If the check engine light is caused by an internal PCM failure (like code P0601), then yes, this will resolve the issue. However, you should always diagnose other potential codes to ensure there aren’t separate issues with sensors or other components.