Restore Your GM Vehicle’s Performance and Reliability
If you’re dealing with a frustrating no-start condition, a persistent Check Engine light, or erratic engine behavior in your 1999 Oldsmobile Alero, the culprit is often the Powertrain Control Module (PCM). As a technician with over two decades of experience, I’ve seen firsthand how a failing engine computer can cause a cascade of confusing problems. This isn’t just a part; it’s the brain of your vehicle’s engine and transmission, and when it falters, nothing runs right. This replacement PCM, part number 9357440, is the definitive solution to get your car back to factory-spec operation without the hassle and expense of a dealership visit.
What sets this module apart is our professional programming service. Before we ship it, we flash the unit with the latest official GM software updates, tailored specifically to your vehicle’s Vehicle Identification Number (VIN). This ensures perfect communication between the engine, transmission, and other onboard systems, restoring fuel efficiency, smooth shifting, and proper engine timing. You get a component that’s ready to install right out of the box, eliminating the need for expensive scan tools or programming appointments.
Case Study: A Tricky Diagnosis
I remember a 1999 Grand Am with the 3.4L V6 that came into my shop. The owner was frustrated—he’d replaced the spark plugs, wires, and even the fuel pump chasing an intermittent stalling issue and a P0601 (Internal Control Module Memory Check Sum Error) code that would come and go. The car would run fine for days, then suddenly die at a stoplight. After verifying the power and ground circuits to the computer were solid, we knew the issue was internal to the module itself. A failing processor was causing the memory corruption. We installed a VIN-programmed PCM just like this one, performed the security relearn, and the car ran perfectly. It’s a classic example of how a faulty 1999 Alero PCM (or in that case, Grand Am) can mimic other component failures, making a reliable replacement essential.
Is Your Vehicle Showing These Symptoms?
A failing PCM can manifest in numerous ways. If you’re experiencing any of the following, your engine computer is a likely suspect:
- ✔ Check Engine Light is on with codes related to internal module failure (e.g., P0601, P0606).
- ✔ Engine cranks but refuses to start.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Unexplained drop in fuel economy.
- ✔ Intermittent stalling, stumbling, or hesitation during acceleration.
- ✔ Failure to pass an emissions or smog test.
- ✔ Communication errors with diagnostic scan tools.
A Straightforward Guide to Installation
Replacing the 1999 Alero PCM is a job most DIY mechanics can handle. The key is taking your time and following the proper procedure, especially the security relearn at the end.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the PCM: On the 1999 Alero, the PCM is typically located in the left-hand (driver’s side) center dash area. You may need to remove a lower dash panel for access.
- Disconnect Connectors: Carefully unclip the wiring harness connectors from the old PCM. These connectors have locking tabs; be gentle to avoid breaking them.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket and remove it from the vehicle.
- Install the New PCM: Mount your new, pre-programmed PCM onto the bracket and securely re-fasten the bolts.
- Reconnect Harnesses: Firmly plug the wiring harnesses back into the new module. You should hear or feel a click as they lock into place.
- Reconnect Battery: Re-attach the negative battery terminal.
- Perform Security Relearn (Crucial Step): Do NOT attempt to start the engine yet. You must perform the GM Passlock/Security relearn procedure. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then ‘OFF’ for 10 seconds, and repeating this cycle three times. This allows the new PCM to synchronize with your vehicle’s anti-theft system.
Verified Vehicle Compatibility
This module, programmed to your VIN, is the correct replacement for a wide range of 1998 and 1999 General Motors vehicles. It directly replaces service numbers 09356741, 16236757, 9357034, 9357440, and 9366314. Please confirm your vehicle is on this list:
- Alero (1999) – 3.4L Engine, with matching ID number
- Achieva (1998) – 3.1L Engine
- Bonneville (1998)
- Camaro (1998) – 3.8L Engine
- Century (1998) – 3.1L Engine
- Cutlass (1998-1999) – with matching ID number
- Eighty Eight (1998)
- Firebird (1998) – 3.8L Engine
- Grand Am (1998-1999) – 3.1L or 3.4L Engine, with matching ID number
- Grand Prix (1998)
- Intrigue (1998)
- LeSabre (1998) – 3.8L Engine
- Lumina Car (1998)
- Malibu (1998) – 3.1L Engine
- Monte Carlo (1998)
- Park Avenue (1998) – 3.8L Engine
- Regal (1998)
- Riviera (1998) – 3.8L Engine
- Silhouette (1998)
- Skylark (1998) – 3.1L Engine
- Trans Sport (1998)
- Venture (1998) – 3.4L Engine
How does the programming process work?
It’s simple. After you complete your purchase, you’ll need to send us your vehicle’s 17-digit VIN. Our technicians will use this VIN to load the latest, most stable GM-approved software directly onto the module. This ensures it’s a perfect match for your car’s specific configuration.
Do I need to do anything after installation?
Yes. After installing the new 1999 Alero PCM and reconnecting the battery, you MUST perform the vehicle’s security relearn procedure. This is a simple process that does not require any special tools and allows the module to sync with your car’s anti-theft system. Instructions are readily available online or in service manuals for your specific model.
Is this a brand new part?
This is a high-quality, fully tested replacement part that has been professionally prepared and programmed for your vehicle. It is guaranteed to meet or exceed original equipment performance.
Will this fix my transmission problems?
The PCM controls both engine and transmission functions. If your shifting problems are caused by faulty electronic commands from the computer, then yes, this module will resolve them. It cannot fix internal mechanical failures within the transmission itself.
What if I provide the wrong VIN?
Providing the correct VIN is critical. An incorrect VIN will result in the wrong software being loaded, and the module will not function correctly in your vehicle. Please double-check your VIN from your driver’s side door jamb sticker or dashboard plate before sending it to us.