Is Your 1999 Escalade or GM Truck Running Rough?
The Powertrain Control Module (PCM), often called the Engine Control Module (ECM), is the electronic brain of your vehicle. It manages everything from fuel injection and spark timing to transmission shifting and emissions control. When it starts to fail, it can cause a cascade of confusing and frustrating problems that can be difficult to diagnose. If you’re experiencing erratic engine behavior, poor fuel economy, or a persistent Check Engine Light, a faulty PCM could be the culprit.
From the Diagnostic Bay
We had a 1999 GMC Yukon in the shop that was driving the owner crazy. It would stall intermittently at red lights, shift hard from first to second, and occasionally wouldn’t start at all. The owner had already replaced the fuel pump and a few sensors with no luck. After hooking up our scanner, we noticed communication dropouts with the PCM. We swapped in a known-good, programmed module, and all the issues vanished instantly. These older GM PCMs are tough, but after 20+ years, the internal components can degrade, leading to these phantom problems that don’t always set a clear trouble code.
Symptoms of a Failing Powertrain Control Module
- ✔ Check Engine Light: The light may be on constantly or intermittently, often with communication-related codes (U-codes) or multiple false sensor codes.
- ✔ No-Start or Hard Starting: The engine may crank but refuse to start, or take an unusually long time to fire up, especially when warm.
- ✔ Poor Engine Performance: You might notice a significant loss of power, hesitation during acceleration, rough idling, or engine stalling.
- ✔ Erratic Transmission Shifting: The PCM also controls the transmission. A failing module can cause harsh shifts, delayed engagement, or getting stuck in one gear.
- ✔ Reduced Fuel Economy: When the PCM can’t properly manage the engine’s fuel and air mixture, your gas mileage will suffer.
- ✔ Failure to Pass Emissions Test: An improperly functioning PCM will prevent the vehicle’s emissions systems from operating correctly.
The Direct-Fit Solution: A VIN-Programmed 1999 Escalade PCM
Don’t let a faulty computer keep your truck off the road. This is a genuine, used OEM Powertrain Control Module that has been thoroughly tested and is ready for installation. The key to a successful repair is proper programming. We take the guesswork out of the equation by flashing this module with the latest GM-approved software updates, specifically matched to your vehicle’s Vehicle Identification Number (VIN). This ensures that all parameters for your engine, transmission, and options are correct right out of the box.
This unit is a direct replacement for multiple GM part numbers, including 09355699, 16266645, 16250279, 16258815, and 9366810. It fits a wide range of popular 1998 and 1999 GM trucks and vans, such as the Chevrolet Tahoe, Suburban, C/K Pickups, Express Van, and their GMC counterparts like the Yukon, Sierra, and Savana. Please verify your part number and consult the detailed fitment list to ensure compatibility.
How It Works:
- Place Your Order: Add this PCM to your cart and complete the checkout process.
- Provide Your VIN: After your purchase, reply to your order confirmation email with your vehicle’s 17-digit VIN. This is critical for the programming service.
- We Program & Ship: Our technicians will flash the module with your vehicle’s specific data. We then ship the ready-to-install computer directly to you.
Upon installation, you may need to perform a simple security relearn procedure (often called Passlock or CASE relearn). This can typically be done without special tools and instructions are widely available online or in service manuals. This synchronizes the new PCM with your vehicle’s anti-theft system.
Will this PCM be plug-and-play?
Yes, for the most part. Because we program it to your VIN, it will have the correct software for your engine and transmission. However, on many GM vehicles of this era, you will need to perform a security relearn procedure to sync the computer with your keys and anti-theft system. This procedure can usually be done in your driveway without any special tools.
How do I provide my VIN?
After you complete your purchase, you will receive an order confirmation email. Simply reply to that email with your 17-digit VIN. You can find your VIN on your vehicle’s dashboard (visible through the windshield), on the driver’s side door jamb sticker, or on your insurance and registration documents.
Is this a new part?
No, this is a high-quality, tested, and fully functional used OEM part sourced from a salvaged vehicle. This provides the reliability of a genuine GM part at a fraction of the cost of a new one.
What if my original part number is slightly different?
This module is a direct replacement for several part numbers, including 09355699, 16266645, 9355699, 16250279, 16258815, and 09366810. As long as your original part number is on this list, this computer will work for your vehicle once programmed.
Do I need any special tools for installation?
Installation typically requires only basic hand tools, such as a socket set, to disconnect the battery and remove the mounting brackets for the PCM. No special diagnostic equipment is needed for the physical installation.