Is Your 1999 Grand Am or Alero Running Rough?
If you’re dealing with a frustrating no-start condition, intermittent stalling, a persistent check engine light, or erratic engine behavior in your 1999 Pontiac Grand Am or Oldsmobile Alero, a failing Engine Control Module (ECM) is a very likely culprit. Over my 20+ years in the garage, I’ve seen countless GM 3.4L engines from this era develop these exact issues. The ECM is the brain of your engine, and when it starts to fail, it can cause a cascade of problems that are often difficult to diagnose.
The Simple, Reliable Solution for Your Vehicle
Forget expensive dealership visits and the hassle of finding a local shop that can program a replacement computer. This ECM is the straightforward answer. We take all the guesswork out of the repair by pre-programming the module specifically for your car using your Vehicle Identification Number (VIN). This ensures it arrives loaded with the latest GM software updates, ready for a direct, simple installation.
Expert Pro Tip: Check This Before You Replace
Before you condemn your old ECM, take 10 minutes to inspect the main ground connections. On these vehicles, the primary ground strap from the engine block to the chassis/frame can corrode over time. A poor ground creates electrical resistance and can cause bizarre symptoms—like flickering lights, gauge issues, and stalling—that perfectly mimic a failing ECM. Cleaning the contact points with a wire brush is a simple check that has saved my customers hundreds of dollars in unnecessary parts.
Common Symptoms of a Failing 1999 Grand Am ECM:
- ✔ Check Engine Light is on with various communication or sensor codes.
- ✔ The engine cranks but refuses to start.
- ✔ Intermittent stalling, especially when the engine is warm.
- ✔ Noticeable decrease in fuel economy and engine performance.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Communication failure with diagnostic scan tools.
Plug-and-Play Installation: No Dealer Visit Required
This module is prepared to make your repair as simple as possible. Once you receive your VIN-programmed computer, you can get your car back on the road by following these general steps. This is a job most DIYers with basic tools can handle in their own driveway.
- Safety First: Always disconnect the negative terminal from your car’s battery before starting any electrical work.
- Locate the ECM: On the 1999 Grand Am and Alero, the ECM is typically found inside the vehicle, on the driver’s side of the center dash area. You may need to remove a lower dash panel for access.
- Disconnect Connectors: Carefully unclip the wiring harnesses from the old module. Inspect the connectors for any signs of corrosion or bent pins and clean them if necessary.
- Swap the Modules: Unbolt the old ECM from its mounting bracket and secure the new one in its place.
- Reconnect Everything: Firmly plug the wiring harnesses into your new ECM. Reconnect the negative battery terminal.
- Perform Security Relearn: Your vehicle may require a simple key-cycle security relearn procedure to recognize the new ECM. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times. Your vehicle’s service manual will have the exact steps.
Guaranteed Fitment and Compatibility
This Engine Control Module is a direct replacement for part numbers 09361733 and 9361733. It is specifically for the following vehicles:
- 1999 Pontiac Grand Am with the 3.4L V6 engine
- 1999 Oldsmobile Alero with the 3.4L V6 engine
After purchase, simply provide us with your VIN, and we’ll handle the programming. We ensure the module you receive is 100% compatible and has the correct software for your car’s specific options, restoring its original performance and reliability.