Is Your Grand Am Running Rough? The PCM Might Be the Culprit.
If you’re dealing with frustrating issues like unpredictable stalling at stoplights, erratic transmission shifting, a persistent check engine light, or even a car that won’t start at all, you’re not alone. In my 20+ years as a technician, I’ve seen these symptoms on countless late-90s GM vehicles, and a failing Powertrain Control Module (PCM) is often the root cause. It’s the central computer for your engine and transmission, and when it starts to fail, it can create a cascade of confusing problems that are difficult to diagnose.
I remember a customer’s ’99 Pontiac Grand Am with the 3.4L V6 that came into my shop. He had already spent a small fortune replacing sensors and the fuel pump, but the car still idled poorly and would die intermittently. After hooking up my scan tool, I noticed the data stream from the PCM was erratic—fuel injector pulse width was all over the place. We installed a correctly programmed PCM, and it ran like new. This module is the solution to get your vehicle running reliably again.
The Simple, Reliable Solution: Programmed & Ready to Install
Forget about expensive dealership visits and the hassle of towing your car for programming. This replacement PCM is the answer. We handle the critical step for you:
- ✔ VIN-Specific Programming: Simply provide us with your vehicle’s VIN during checkout. We will flash the module with the latest, most stable GM software updates specific to your car’s exact build.
- ✔ True Plug-and-Play: Because it’s pre-programmed, this module is ready for installation right out of the box. No special tools or dealer appointments are required.
- ✔ Restores Original Performance: A new PCM can resolve a wide range of issues, restoring smooth idling, proper shifting, and optimal fuel efficiency.
Expert Pro Tip: Check Your Connections
Before you plug in your new PCM, take a close look at the vehicle’s harness connectors. After two decades, the plastic can become brittle and the metal pins can develop corrosion or even get pushed back into the connector. Use a small amount of electrical contact cleaner and a flashlight to ensure every pin is clean, straight, and fully seated. A poor connection is the number one reason for a new module to not work correctly, so this five-minute check can save you hours of headaches.
Easy Installation Guide for Your 1998-1999 Grand Am PCM
Replacing the PCM on these vehicles is a straightforward job that most DIY mechanics can handle in under an hour. While locations can vary slightly, it’s typically found under the dash on the driver’s or passenger’s side.
- Safety First: Always disconnect the negative terminal from your car’s battery and wait a few minutes before starting work.
- Locate the Module: On many Grand Am and Alero models, the PCM is located behind the lower left-hand side of the dashboard.
- Disconnect Connectors: Carefully unclip the wiring harness connectors from the old PCM. Be gentle, as the plastic clips can be brittle.
- Remove Old PCM: Unbolt the module from its mounting bracket and remove it from the vehicle.
- Install New PCM: Mount your new, pre-programmed PCM in place and secure the bolts.
- Reconnect Everything: Firmly plug the wiring harnesses back into the new module until they click. Reconnect your negative battery terminal.
- Security Relearn: Your vehicle may require a simple security relearn procedure. This usually involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times before starting the engine.
Guaranteed Compatibility
This module is a direct replacement for several GM vehicles. Please verify that your original module has one of the following service numbers printed on the label:
Service Numbers: 09356741, 16236757, 9357034, 9357440, 9366314
This part will fit these makes and models with these options:
ACHIEVA 98 (3.1L), ALERO 99 (3.4L), BONNEVILLE 98, CAMARO 98 (3.8L), CENTURY 98 (3.1L), CUTLASS 98-99, EIGHTY EIGHT 98, FIREBIRD 98 (3.8L), GRAND AM 98 (3.1L), GRAND AM 99 (3.4L), GRAND PRIX 98, INTRIGUE 98, LESABRE 98 (3.8L), LUMINA CAR 98, MALIBU 98 (3.1L), MONTE CARLO 98, PARK AVENUE 98 (3.8L), REGAL 98, RIVIERA 98 (3.8L), SILHOUETTE 98, SKYLARK 98 (3.1L), TRANS SPORT 98, VENTURE 98 (3.4L)