Is Your Oldsmobile Alero Running Rough? Get Back on the Road Fast.
As a technician with over two decades of experience under the hood, I’ve seen countless GM vehicles from this era come into the shop with frustrating, hard-to-diagnose issues. A flickering check engine light, erratic shifting, a sudden drop in fuel economy, or even a car that refuses to start can often be traced back to one single component: a failing Powertrain Control Module (PCM). This isn’t just a part; it’s the brain of your vehicle, and when it starts to falter, the symptoms can be all over the map. This replacement PCM is the direct, reliable solution for your 1999 Oldsmobile Alero and a wide range of other GM models.
The Most Common Symptoms of a Failing GM PCM
If your vehicle is experiencing any of the following, a faulty PCM is a very likely culprit. In my shop, I’ve seen these exact issues resolved hundreds of times by replacing this specific module.
- ✔ Persistent Check Engine Light (CEL) that won’t clear
- ✔ Harsh or delayed automatic transmission shifting
- ✔ Unexplained decrease in gas mileage
- ✔ Engine stalling, stumbling, or misfiring
- ✔ No-start or intermittent starting conditions
- ✔ Communication errors with diagnostic scan tools
Expert Pro Tip: Check Your Grounds First!
Before you replace any module, do yourself a favor and perform a simple check. On these late-90s GM vehicles, a corroded or loose main engine-to-chassis ground strap can cause voltage drops that mimic PCM failure. I’ve seen customers spend hundreds on diagnostics when the real fix was a $10 ground strap and 15 minutes with a wire brush and a wrench. Ensure the connection points on the engine block and the chassis are clean, bare metal and tight. It’s a quick check that can save you a lot of headaches.
Why Our 1999 Alero Powertrain Control Module is the Smart Choice
Ordering an electronic part online can feel like a gamble, but we eliminate the guesswork. The biggest hurdle with replacing a PCM is the programming—without it, the car won’t run. Typically, this means buying the part, installing it, and then having your car towed to a dealership for expensive programming. We solve that problem for you.
Programmed Specifically for Your Vehicle: When you purchase from us, you provide your vehicle’s 17-digit VIN. We then flash this module with the latest, most stable software updates directly from GM. This ensures perfect compatibility with your Alero’s specific engine, transmission, and options. It arrives at your door ready to install.
Simple, DIY-Friendly Installation Guide
You don’t need to be a master mechanic to complete this job. With our pre-programmed module, it’s a straightforward swap. Follow these steps to get your car running smoothly again.
- Safety First: Disconnect the negative terminal from your car’s battery and secure it away from the post to prevent any accidental reconnection.
- Locate the PCM: On the 1999 Alero, the PCM is typically located in the left-hand (driver’s side) center dash area, often accessible by removing the lower dash panel.
- Disconnect the Wiring: Carefully unplug the electrical connectors from the old module. These connectors have locking tabs that need to be released. Do not force them.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket. Keep the hardware as you will need it for the new module.
- Install the New Module: Mount your new, pre-programmed PCM onto the bracket and secure it with the original hardware.
- Reconnect Everything: Plug the wiring harnesses firmly into the new module until they click into place. Reconnect your vehicle’s negative battery terminal.
- Final Step: Your vehicle may need to complete a security relearn procedure, which is a simple process you can do in your driveway. Instructions are readily available online or we can provide guidance. This syncs the new PCM with your car’s anti-theft system.
Guaranteed Compatibility
This module is a direct replacement for several original equipment service numbers, ensuring a perfect fit and function. If your original module has any of the following numbers, this part is the correct replacement for you:
Service Numbers: 09356741, 16236757, 9356741, 9357034, 9357440, 9366314
This part is confirmed to fit a wide variety of 1998 and 1999 GM vehicles including the Pontiac Grand Am, Buick Century, Chevrolet Malibu, and many more, as long as the service number on your original part matches. Please verify your part number before ordering to ensure a perfect match.