Is Your GM Truck or Car Acting Possessed? Let’s Talk PCMs.
If you’re dealing with a 1999-2002 GM vehicle, especially a truck like a Yukon, Silverado, or Sierra, you might be pulling your hair out over some truly baffling issues. Maybe it’s a hard start or a no-start condition that comes and goes. Perhaps the transmission is shifting erratically, or you’re getting a storm of random, unrelated check engine light codes. As a technician with over two decades in the bay, I’ve seen this exact scenario hundreds of times. The culprit is almost always the brain of the operation: the Powertrain Control Module (PCM).
A Story From The Shop: The Silverado That Wouldn’t Communicate
“A customer’s 2000 Silverado 1500 was towed in last month. It would crank but never fire up. The owner, a pretty savvy DIYer, had already replaced the fuel pump and the crank sensor, but nothing worked. When I connected my professional scan tool, it simply said, ‘Cannot Communicate with ECM.’ That’s the tell-tale sign. We checked the power and ground wires to the moduleโthey were perfect. The PCM itself was dead. The location on these trucks, right under the battery, makes them vulnerable to corrosion from battery acid leaks, which is exactly what happened here. We installed one of our VIN-programmed modules, performed a quick security relearn, and it fired up on the first try.”
Why Your Original PCM is Failing
The PCM, also known as the ECM or computer, is the master controller for your engine and transmission. It processes data from dozens of sensors to manage fuel injection, spark timing, transmission shift points, and more. On many of the vehicles this part fitsโlike the Tahoe, Suburban, and Sierraโit’s mounted on the driver’s side frame rail, directly beneath the battery tray. Over years, this location exposes it to:
- โ Vibration: Constant shaking from the road and engine can cause microscopic cracks in the circuit board’s solder joints.
- โ Heat Cycles: The constant change from cold to hot engine bay temperatures stresses electronic components, leading to eventual failure.
- โ Moisture & Corrosion: This is the big one. A leaky battery or exposure to road salt and water can corrode the PCM’s casing and, more importantly, the delicate connector pins, causing intermittent or total failure.
Common Symptoms of a Bad GM PCM (Part #9354896)
If you’re nodding along, you’ve likely experienced one or more of these issues. A failing PCM doesn’t always die completely; it often fails intermittently, making diagnosis a nightmare.
- โ Complete no-start or intermittent starting problems.
- โ Engine stalling for no apparent reason while driving or at idle.
- โ Harsh or erratic automatic transmission shifting.
- โ Check Engine Light is on with multiple, often unrelated, diagnostic trouble codes (DTCs).
- โ Poor fuel economy and noticeable loss of power.
- โ Inability for a scan tool to communicate with the vehicle’s computer.
The Solution: A Reliable, Pre-Programmed PCM
You can’t just grab a used PCM from a junkyard and plug it in. GM vehicles of this era use a Vehicle Anti-Theft System (VATS) that marries the PCM to your specific vehicle’s VIN. A mismatched PCM will disable the fuel injectors, and the engine won’t run. This is where we come in.
This PCM is the direct, correct solution for your vehicle. We take all the guesswork and hassle out of the process. Hereโs what we do:
- You place your order and provide us with your vehicle’s 17-digit VIN.
- Our experts use official GM equipment to flash the module with the latest, most stable software specific to your VIN. This ensures all factory drivability and emissions updates are included.
- We ship you a module that is ready for installation. In most cases, you will need to perform a simple 10-30 minute security relearn procedure after installation, which requires only your ignition keyโno special tools needed. We can provide instructions for this.
Guaranteed Fitment for Your Vehicle
This module is a direct replacement for original part numbers 9354896, 09354896, and 19109040. It is guaranteed to fit and function correctly on a wide range of GM models, including:
- โ 1999-2002 Chevrolet Camaro & Pontiac Firebird (5.7L)
- โ 1999-2000 Chevrolet Corvette
- โ 1999-2000 Chevrolet & GMC 1500/2500 Pickups (Silverado/Sierra)
- โ 2000 Chevrolet Tahoe & Suburban
- โ 2000 GMC Yukon & Yukon XL
Please use the fitment chart to confirm your specific model and year. Installing this module is the most effective way to permanently resolve the frustrating electronic issues plaguing your vehicle and restore its factory performance and reliability. Don’t let a faulty computer keep you off the road.