Restore Your Truck’s Performance and Reliability
Is your 1999-2000 GMC Sierra 1500 experiencing frustrating issues like a persistent check engine light, erratic shifting, a no-start condition, or poor fuel economy? These are classic signs of a failing Powertrain Control Module (PCM), the electronic brain of your vehicle. In my 20+ years of diagnosing GM trucks, I’ve seen countless vehicles sidelined by a faulty computer. This replacement PCM is the definitive solution to get your dependable truck back on the road, running exactly as it should.
We take the guesswork and hassle out of the repair. Unlike sourcing a module from a salvage yard, this unit comes professionally programmed to your truck’s specific Vehicle Identification Number (VIN). We install the latest GM-authorized software updates, which can resolve underlying drivability issues you might not even know were software-related. This ensures perfect communication between the engine, transmission, and other vehicle systems, restoring factory performance and efficiency. A failing computer can be a headache, but this direct-fit, pre-programmed 1999-2000 Sierra 1500 PCM makes the fix straightforward and reliable.
From the Diagnostic Bay: The Ghost in the Machine
A customer brought in his ’99 Silverado with the same V8 powertrain as your Sierra. The complaint was intermittent stalling at stoplights and a weird, delayed shift from 1st to 2nd gear. There were no consistent trouble codes, just a generic U-code for lost communication that would pop up randomly. We checked everything—fuel pressure, wiring harnesses, sensors—and couldn’t find a physical fault. After hours of diagnostics, I suspected the PCM itself. The internal processors can weaken over time, causing these bizarre, unpredictable symptoms. We installed a VIN-programmed PCM just like this one. The truck immediately ran perfectly, the shifting smoothed out, and the ghost electrical gremlins were gone for good. It’s a reminder that sometimes the most confusing problems have the simplest solution: a reliable, correctly programmed computer.
Common Signs of a Failing PCM in Your GM Truck
- ✔ Check Engine Light is on with codes like P0601, P0602, or P0606 (Internal Control Module Memory Check Sum Error or Processor Fault).
- ✔ Vehicle refuses to start or stalls unexpectedly.
- ✔ Noticeable drop in fuel mileage.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Engine runs rough, misfires, or hesitates during acceleration.
- ✔ Failure to communicate with a diagnostic scan tool.
Your Straightforward PCM Swap Guide
- ✔ Safety First: Disconnect the negative terminal from your truck’s battery to prevent any electrical shorts.
- ✔ Locate the PCM: On most 1999-2000 GM trucks, the PCM is located on the driver’s side frame rail, underneath the battery and airbox. You may need to remove the battery and its tray for access.
- ✔ Disconnect the Module: Carefully unplug the electrical connectors. These have locking tabs that need to be released. Never force them. Note the color-coding of the connectors and their respective ports.
- ✔ Swap the Units: Unbolt the old PCM from its mounting bracket and install the new one in its place.
- ✔ Reconnect Everything: Plug the electrical connectors securely into their correct ports on the new PCM. Reinstall the battery tray and battery, then reconnect the negative battery terminal.
- ✔ Perform Security Relearn: After installation, you will likely need to perform a security relearn procedure (often called Passlock relearn) so the vehicle recognizes the new PCM. This procedure can typically be done without special tools and instructions are widely available online. A crankshaft variation relearn (CASE learn) may also be required, which needs a capable scan tool.
By purchasing a pre-programmed 1999-2000 Sierra 1500 PCM, you are getting the most critical part of the job done for you, saving you a costly trip to the dealership for programming.
Verified Fitment for These GM Vehicles
This module, also known by part numbers 09354896 and 9354896, is a direct replacement for a wide range of GM cars and trucks. Please verify your vehicle is on this list:
CORVETTE: 1999-2000
FIREBIRD: 1999-2002 (5.7L)
SIERRA 1500 PICKUP: 1999-2000 (V8 Models)
SIERRA 2500 PICKUP: 1999-2000
SILVERADO 1500 PICKUP: 1999-2000 (V8 Models)
SILVERADO 2500 PICKUP: 1999-2000
SUBURBAN 1500/2500: 2000
TAHOE: 2000 (Silverado Body Style)
YUKON: 2000 (Excluding Denali)
YUKON XL 1500/2500: 2000
Frequently Asked Questions
How do I provide my VIN for programming?
After you complete your purchase, simply send us a message with your 17-digit Vehicle Identification Number (VIN). We cannot ship the module until we receive your VIN, as the programming is specific to your vehicle.
Is this a plug-and-play part?
Almost. The main programming is done for you. However, after installation, you will need to perform a security relearn procedure for the vehicle’s anti-theft system to recognize the new PCM. Some vehicles may also require a crankshaft position sensor variation relearn (CASE learn) with a compatible scan tool to clear a P1336 code and ensure optimal engine timing.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM controls the engine and transmission. If the computer is failing, it can send incorrect signals to the transmission, causing harsh or erratic shifts. A new, properly programmed PCM often resolves these issues, provided the transmission itself is mechanically sound.
What’s the difference between a PCM and an ECM?
The terms are often used interchangeably. ECM stands for Engine Control Module, while PCM stands for Powertrain Control Module. A PCM is an ECM that also controls the transmission and other powertrain functions. For your 1999-2000 Sierra 1500 PCM, it controls both, so PCM is the more accurate term.