Restore Your Vehicle’s Brain and Get Back on the Road
As a technician with over two decades of experience under the hood, I’ve seen countless vehicles sidelined by a faulty Powertrain Control Module (PCM). A bad PCM can cause some of the most frustrating and hard-to-diagnose problems, from a simple no-start condition to erratic shifting and abysmal fuel economy. If your 1999 Cadillac Escalade, or one of the many compatible GM trucks and vans, is acting up, this reliable, tested engine computer is your direct-fit solution.
This isn’t just a part in a box. This is a complete, ready-to-install solution. We take a genuine, used OEM computer and professionally flash it with the latest GM-certified software updates, specifically matched to your vehicle’s VIN. This critical step ensures that all factory parameters for fuel delivery, ignition timing, and transmission shifting are perfectly calibrated for your engine and drivetrain. You get the performance and reliability of a properly functioning computer without the steep cost and programming hassle of a dealership visit. This is the smart, efficient way to solve complex electronic issues and restore your vehicle’s core performance.
From the Diagnostic Bay: The ‘No-Start’ ’99 Suburban
I remember a 1999 Suburban rolling into my shop on a tow truck. The owner was frustrated; he’d replaced the fuel pump and the ignition coil, but it still wouldn’t fire up consistently. The scanner was throwing a P0601 (Internal Control Module Memory Check Sum Error) code, a classic sign of PCM failure. Instead of a costly new unit and a day lost to dealer programming, we sourced a tested, used PCM just like this one. We had it programmed to his VIN, installed it in under 30 minutes, performed the security relearn, and the truck fired up on the first try. He drove away with a reliable vehicle and saved hundreds of dollars.
Is Your Truck or SUV Showing These Signs?
A failing PCM can manifest in various ways. If you’re experiencing any of the following, your engine computer could be the culprit. These symptoms are often accompanied by diagnostic trouble codes (DTCs) like P0601, P0602, or P0606.
- ✔ Check Engine Light is on or flashing
- ✔ Vehicle refuses to start or has intermittent starting issues
- ✔ Rough idling or stalling
- ✔ Noticeable decrease in fuel efficiency
- ✔ Harsh or erratic automatic transmission shifting
- ✔ Engine misfires or stumbles during acceleration
- ✔ Failure to pass an emissions test
Your Straightforward PCM Installation Guide
Installing your pre-programmed 1999 Escalade PCM is a manageable job for a DIYer with basic tools. The key is following the steps carefully, especially the security relearn procedure.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the PCM: On most of these GM trucks and vans, the PCM is located in the engine compartment, typically on the driver’s side fender or near the battery. It’s a silver metal box with several large electrical connectors.
- Disconnect Connectors: Carefully unclip and remove all electrical harness connectors from the old PCM. They often have locking tabs that need to be released.
- Remove the Old Unit: Unbolt the old PCM from its mounting bracket. Keep the hardware as you will need it for the new unit.
- Install the New PCM: Mount your new, pre-programmed PCM onto the bracket and securely fasten it. Reconnect all electrical connectors, ensuring they click into place.
- Reconnect Battery: Reattach the negative battery terminal.
- Perform Security Relearn (CRITICAL STEP): Do not skip this. The vehicle will not start without it. Turn the key to the “ON” position (do not start) for 10-15 minutes. The security light should turn off. Turn the key to “OFF” for 10 seconds. Repeat this cycle two more times (for a total of three cycles). After the third cycle, the vehicle should start and run normally.
Verified Vehicle Compatibility List
This module is a direct replacement for service number 09366810 and interchanges with part numbers 09355699, 16266645, 16250279, and 16258815. Please verify your part number or match your vehicle from the list below. This unit fits a wide range of GM models with service ID 9355699.
- Cadillac Escalade: 1999
- Chevrolet Astro Van: 1998
- Chevrolet Blazer S10: 1998
- Chevrolet C/K 1500/2500/3500 Pickup: 1998-1999 (Gas)
- Chevrolet Express 1500/2500/3500 Van: 1998-1999 (Gas)
- Chevrolet Suburban 1500/2500: 1998-1999 (Gas)
- Chevrolet Tahoe: 1998-1999 (Gas)
- GMC Envoy: 1998
- GMC Jimmy S15: 1998
- GMC C/K 1500/2500/3500 Pickup: 1998-1999 (Gas)
- GMC Safari Van: 1998
- GMC Savana 1500/2500/3500 Van: 1998-1999 (Gas)
- GMC Sonoma S15: 1998
- GMC Yukon: 1998-1999
- Isuzu Hombre: 1998 (4.3L)
- Oldsmobile Bravada: 1998
Why do I need to provide my VIN?
Your Vehicle Identification Number (VIN) is essential. We use it to load the exact, correct GM software for your vehicle’s specific engine, transmission, and options. This ensures perfect compatibility and function right out of the box, eliminating the need for expensive dealer programming.
Is this part difficult to install?
For someone with basic mechanical skills, the physical swap is straightforward. The most important part is the security relearn procedure, which requires no tools but must be followed precisely. Our guide above walks you through the entire process.
What is the security relearn procedure?
It’s a process that syncs your new PCM with your vehicle’s anti-theft system. Without it, the system will prevent the engine from starting. It involves a simple sequence of turning the key on and off for set periods, as detailed in our installation guide.
Is a used PCM a reliable choice?
Absolutely. These OEM units were built to last. We source quality parts from salvaged vehicles and test them to ensure they are fully functional. This provides an excellent, cost-effective alternative to a brand-new part, giving you OEM quality without the high price tag.
This is for a 1999 Escalade PCM, but will it fit my Chevy truck?
Yes. This specific PCM model was used across a vast number of GM trucks and vans from 1998-1999. As long as your vehicle is on our compatibility list and your original part number matches one of the listed interchanges, this module will be a perfect fit when programmed to your VIN.
What happens if I don’t perform the security relearn?
If the security relearn is not performed correctly, the vehicle’s anti-theft system will remain active and will not allow the engine to start. It’s a simple but mandatory step for the PCM to function in your vehicle.