Restore Your Vehicle’s Performance and Reliability
If you’re dealing with frustrating issues like a persistent check engine light, erratic engine behavior, poor fuel economy, or even a no-start condition, the culprit is often the Powertrain Control Module (PCM). As the central computer for your engine and transmission, a failing PCM can cause a cascade of problems that can be difficult to diagnose. I’ve spent two decades in the garage, and I’ve seen firsthand how a faulty module can mimic a dozen other issues. This isn’t just a replacement part; it’s the solution to get your vehicle running smoothly and reliably again.
This PCM is a direct-fit replacement for a wide range of late-90s GM vehicles. The best part? We handle the programming for you. Simply provide your vehicle’s VIN during checkout, and we will flash the module with the latest GM-certified software specific to your car. This means no expensive trip to the dealership for programming. It arrives at your door ready to install, saving you time, money, and headaches. This is the exact process we use in my shop to ensure a perfect, hassle-free repair.
A Technician’s Notebook: The Case of the Intermittent Grand Am
A customer brought in a ’99 Pontiac Grand Am with the 3.4L V6—a vehicle that uses this exact module. The complaint was maddening: it would run perfectly for days, then suddenly stall at a red light or refuse to start after being parked for an hour. There were no consistent codes, just a general history of communication errors. After checking all the usual suspects—fuel pressure, crank sensor, wiring—we focused on the PCM. On the bench, we found that heat soak was causing an internal circuit to fail intermittently. We installed one of these pre-programmed PCMs, and the car has run flawlessly for the owner ever since. It’s a classic failure mode for these units, and this part is the definitive fix.
Common Signs of a Failing GM PCM
- ✔ Check Engine Light is on with codes related to internal module failure (e.g., P0601, P0605).
- ✔ Vehicle has difficulty starting or won’t start at all.
- ✔ Unexplained drop in fuel efficiency.
- ✔ Engine stumbling, stalling, or running rough.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Loss of communication with the diagnostic scan tool.
A Straightforward Guide to Installation
Replacing the 1999 Alero PCM is a job most DIYers with basic tools can handle. While the exact location can vary slightly by model, the process is generally similar.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the Module: On many models like the Alero and Grand Am, the PCM is found in the center of the dash, often accessible by removing the glove box or a lower dash panel. On vans like the Venture or Silhouette, it’s typically in the engine compartment.
- Disconnect Connectors: Carefully unclip the wiring harness connectors from the old PCM. These connectors have locking tabs that need to be released. Avoid pulling on the wires themselves.
- Remove the Old PCM: Unbolt the module from its mounting bracket. It’s usually held in by a few small bolts or nuts.
- Install the New PCM: Mount your new, pre-programmed PCM onto the bracket and secure it.
- Reconnect Everything: Firmly plug the wiring harnesses back into the new module until they click into place. Reconnect the negative battery terminal.
- Final Step: In some cases, a security relearn procedure may be necessary. This can typically be done by turning the key to the ‘ON’ position for 10-15 minutes. Consult your vehicle’s service information for specific steps.
Verified Vehicle Compatibility
This module is a direct replacement for units with service numbers 09356741, 16236757, 9357034, 9357440, or 9366314. It is guaranteed to fit the following models with the specified options:
- ACHIEVA 98 (6-191, 3.1L)
- ALERO 99 (LH center dash, 3.4L, with matching ID)
- BONNEVILLE 98
- CAMARO 98 (6-231, 3.8L)
- CENTURY 98 (6-191, 3.1L)
- CUTLASS 98 & 99 (with matching ID)
- EIGHTY EIGHT 98
- FIREBIRD 98 (6-231, 3.8L)
- GRAND AM 98-99 (with matching engine/ID)
- GRAND PRIX 98
- INTRIGUE 98
- LESABRE 98 (6-231, 3.8L)
- LUMINA CAR 98 (LH engine compartment)
- MALIBU 98 (6-191, 3.1L)
- MONTE CARLO 98
- PARK AVENUE 98 (6-231, 3.8L)
- REGAL 98
- RIVIERA 98 (6-231, 3.8L)
- SILHOUETTE 98 (LH engine compartment)
- SKYLARK 98 (6-191, 3.1L)
- TRANS SPORT 98 (LH engine compartment)
- VENTURE 98 (6-207, 3.4L)
Do I need to get this PCM programmed?
Do I need to get this PCM programmed?
No. We program the module for you before it ships. All we need is your vehicle’s 17-digit VIN (Vehicle Identification Number) to load the correct, updated software. It arrives ready for installation.
Where do I find my VIN?
Your VIN is located on a metal tag on the driver’s side of the dashboard (visible through the windshield), on the driver’s side door jamb sticker, and on your vehicle’s registration and insurance documents.
Will this fix my specific problem?
While this 1999 Alero PCM is the solution for a failed module, it’s crucial to ensure your vehicle has been properly diagnosed. This part will resolve issues directly caused by a faulty PCM, such as internal errors, but it will not fix problems from other bad sensors or wiring issues.
What if I don’t provide my VIN?
We cannot ship the module without a VIN. The programming is essential for the part to function in your vehicle. It ensures compatibility with your engine, transmission, and other systems. We will hold your order and contact you for the VIN.
Is any other setup required after installation?
In most cases, no. However, some GM vehicles may require a simple, key-on security relearn procedure to sync the new PCM with the anti-theft system. This procedure does not require special tools and can be found in your vehicle’s service information or online.