Restore Your Vehicle’s Performance and Reliability
If you’re dealing with a frustrating check engine light, poor fuel economy, stalling, or erratic transmission shifting in your 1999 Oldsmobile Alero or other compatible GM vehicle, a failing Powertrain Control Module (PCM) is often the culprit. As the central computer of your car, the PCM manages everything from fuel injection and spark timing to transmission shift points. When it fails, the symptoms can be unpredictable and maddening. I’ve seen countless vehicles in my bay with these exact issues, where owners have spent hundreds chasing sensors, only to find the core problem was the PCM itself.
This isn’t just a replacement part; it’s a complete, hassle-free solution. We take the guesswork and the expensive trip to the dealership out of the equation. Each module is professionally programmed with the latest GM software updates specifically for your vehicle’s VIN. This ensures perfect communication between your engine, transmission, and other onboard systems, restoring the smooth, efficient performance you expect.
A Technician’s Notebook
I remember a 1998 Grand Prix that came into the shop with an intermittent no-start condition that was driving the owner crazy. It would be fine for days, then refuse to start. No check engine light, no obvious cause. After checking the fuel pressure, spark, and crank sensor signals—all of which tested fine—we hooked up a high-end scanner to monitor data streams. We noticed that during the no-start events, the PCM wasn’t commanding the fuel injectors to fire. The module itself was failing internally when it heated up. We installed a VIN-programmed PCM just like this one, and the car started reliably every single time. It’s a classic example of how a faulty computer can mimic other failures, making a direct-fit, pre-programmed part the most efficient repair.
Is Your GM Vehicle Showing These PCM Failure Signs?
A failing computer can cause a wide range of problems. If you’re experiencing any of the following, it might be time to replace your PCM:
- ✔ Persistent Check Engine Light (CEL) that won’t clear
- ✔ Diagnostic Trouble Codes (DTCs) related to internal module failure, such as P0601, P0603, or P0605
- ✔ Unexplained drop in fuel mileage
- ✔ Engine stalling, sputtering, or refusing to start
- ✔ Harsh or erratic automatic transmission shifting
- ✔ Failure to pass an emissions or smog test
- ✔ Communication errors with diagnostic scan tools
Simple Steps to Get Your Car Running Right
Installing your new 1999 Alero PCM is a straightforward process that most DIYers can handle. Since it arrives pre-programmed, you won’t need any special scan tools for the initial setup.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the Old PCM: On most of these vehicles, the PCM is located in the engine compartment or under the dash. On the Alero and Grand Am, it’s typically found on the left-hand (driver’s) side, center of the dash.
- Disconnect and Remove: Carefully unplug the wiring harness connectors. They have locking tabs that need to be released. Once disconnected, unbolt the old module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed PCM into place. Reconnect the wiring harnesses, making sure they click securely into position.
- Reconnect the Battery: Reattach the negative battery terminal.
- Perform Security Relearn (If Necessary): Some GM vehicles of this era require a simple key-cycle security relearn procedure to sync the new PCM with the anti-theft system. This usually involves turning the key to the ‘ON’ position for 10-15 minutes. We include instructions for this simple procedure.
Verified Compatibility for Your GM Vehicle
This module is a direct-fit replacement for a wide range of GM cars and vans. Please verify your vehicle and engine size below. This part is compatible with service numbers: 09356741, 16236757, 9357034, 9357440, and 9366314.
1999 Pontiac Grand Am: (LH center dash), 3.4L, with matching ID number
1998 Buick Century: (6-191, 3.1L)
1998 Buick LeSabre: (6-231, 3.8L)
1998 Buick Park Avenue: (6-231, 3.8L)
1998 Buick Regal / Riviera / Skylark
1998 Chevrolet Camaro / Firebird: (6-231, 3.8L)
1998 Chevrolet Lumina / Monte Carlo
1998 Chevrolet Malibu: (6-191, 3.1L)
1998 Chevrolet Venture: (6-207, 3.4L)
1998 Oldsmobile Achieva / Cutlass / Eighty Eight / Intrigue / Silhouette
1998 Pontiac Bonneville / Grand Prix / Trans Sport
1999 Oldsmobile Cutlass: (LH center dash), with ID 16236757
Frequently Asked Questions
How does the VIN programming process work?
After you complete your purchase, you will need to provide us with your vehicle’s 17-digit VIN. Our technicians use this number to flash the module with the correct, vehicle-specific software and the latest updates from GM before it ships. This ensures it’s ready for installation right out of the box.
Is this a plug-and-play part?
Yes, for most vehicles. Because it’s pre-programmed to your VIN, you will not need a dealer-level scan tool for setup. Some vehicles may require a simple security relearn procedure, which involves a few key cycles and takes about 30 minutes. Instructions are provided.
Will this fix my check engine light?
If the check engine light is caused by a faulty PCM (e.g., code P0601), this part will resolve the issue. It’s crucial to properly diagnose the problem first, as a CEL can be caused by many other components like sensors or wiring issues.
Do I need to send my old PCM back?
No core charge or return is required for this part. You can recycle your old module locally.
Where is the service number located on my original part?
The service number is typically printed on a sticker on the case of your original PCM. Matching one of the listed service numbers (e.g., 16236757, 09356741) helps confirm compatibility.