Restore Peak Performance to Your GM Vehicle
If you’re battling a persistent Check Engine Light, experiencing erratic engine behavior, poor fuel mileage, or harsh transmission shifts, the problem often lies with a failing Powertrain Control Module (PCM). As a technician with over two decades of experience under the hood, I’ve seen firsthand how a faulty PCM can create a cascade of frustrating, hard-to-diagnose issues. This isn’t just a component; it’s the central computer for your engine and transmission. This replacement 1999 Alero Powertrain Control Module is the definitive solution to get your vehicle running reliably again.
The biggest hurdle with PCM replacement has always been the expensive and time-consuming programming required at a dealership. We eliminate that completely. Before this module ships, we flash it with the latest official GM software updates, tailored specifically to your vehicle using the VIN you provide. This means it arrives at your door ready for a straightforward installation, saving you time, money, and hassle.
From the Diagnostic Bay: The Ghost in the Grand Prix
I remember a 1998 Pontiac Grand Prix that came into the shop with a maddening intermittent no-start condition. The owner had already replaced the battery, starter, and crank sensor. It would run fine for days, then refuse to start for an hour. No clear codes, just chaos. After checking all the wiring, we focused on the PCM. On a hunch, we connected a scope and saw the 5-volt reference signal dropping out randomly. A replacement PCM, programmed to the car’s VIN, solved the problem instantly. It’s a classic example of how a failing module can mimic other component failures, costing you time and money on parts you don’t need.
Common Signs of a Failing GM PCM
A failing engine computer can manifest in numerous ways. If your vehicle is showing any of these signs, a faulty PCM is a likely culprit. Keep an eye out for Diagnostic Trouble Codes (DTCs) like P0601, P0602, or P0606, which point directly to an internal module fault.
- ✔ Persistent Check Engine Light (CEL) that won’t clear
- ✔ Engine stalling, stumbling, or rough idling
- ✔ A noticeable decrease in fuel economy
- ✔ Harsh or erratic automatic transmission shifting
- ✔ Failure to pass state emissions testing
- ✔ Intermittent or complete no-start condition
- ✔ Communication errors with diagnostic scan tools
A Straightforward Guide to Installation
Installing your new 1999 Alero Powertrain Control Module is a job most DIYers can handle with basic tools. Since it comes pre-programmed, no special electronic equipment is needed.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the PCM: On most of these GM models, the PCM is located inside the vehicle’s air filter box in the engine compartment or under the dash on the passenger side. A quick search for your specific model will confirm its location.
- Disconnect the Old Module: Carefully unplug the electrical harness connectors. They have locking tabs that need to be released—be gentle to avoid breaking them. Once disconnected, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed PCM into place. Securely reconnect the electrical harnesses, ensuring they click and lock into position.
- Reconnect and Start: Reconnect the negative battery terminal. The vehicle may run slightly rough for the first few minutes as the new module completes an idle air relearn procedure. Let it idle for 5-10 minutes before driving.
Verified Vehicle Compatibility
This module is a direct-fit replacement for a wide range of GM vehicles from the late 1990s. It is compatible with service part numbers 09356741, 16236757, 9356741, 9357034, 9357440, and 9366314. Please verify your vehicle and options below to ensure proper fitment. This is a crucial step for a successful repair, especially for the 1999 Alero Powertrain Control Module.
ALERO 99: 3.4L (LH center dash), ID 16236757, 9356741, 9357034, or 9357440
BONNEVILLE 98: All models
CAMARO 98: 6-231 (3.8L)
CENTURY 98: 6-191 (3.1L)
CUTLASS 98: All models
CUTLASS 99: (LH center dash), ID 16236757
EIGHTY EIGHT 98: All models
FIREBIRD 98: 6-231 (3.8L)
GRAND AM 98: 6-191 (3.1L)
GRAND AM 99: 3.4L (LH center dash), ID 16236757, 9356741, 9366314, 9357034, or 9347440
GRAND PRIX 98: All models
INTRIGUE 98: All models
LESABRE 98: 6-231 (3.8L)
LUMINA CAR 98: (LH engine compartment)
MALIBU 98: 6-191 (3.1L)
MONTE CARLO 98: All models
PARK AVENUE 98: 6-231 (3.8L)
REGAL 98: All models
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)
Frequently Asked Questions
What is VIN programming and why is it important?
VIN programming is the process of loading your vehicle’s specific software onto the PCM. It ensures the module works correctly with your engine, transmission, and all factory options. Our pre-programming service saves you a trip to the dealer and ensures a plug-and-play installation.
Do I need to do anything after I install this PCM?
No special procedures are required. After installation, just start the vehicle and let it idle for 5-10 minutes to allow the computer to learn the engine’s idle parameters. Some vehicles may also require a security relearn procedure, which can typically be done without tools by cycling the key. Instructions are widely available online for your specific model.
Will this fix my check engine light?
If the check engine light is caused by a faulty PCM (common codes P0601-P0606) or a software-related issue that the latest GM updates address, then yes, this module will resolve the light. It’s crucial to ensure the light isn’t caused by another faulty sensor or component.
Where is the PCM located on my 1999 Alero?
On the 1999 Oldsmobile Alero, the Powertrain Control Module is typically located on the driver’s side of the engine compartment, inside the plastic air filter housing assembly. You will need to open the airbox to access it.
My original part number isn’t an exact match, but it’s on your compatible list. Will it work?
Yes. Manufacturers often use several interchangeable service numbers for the same part. As long as your vehicle model and engine are on our fitment list and your original service number is one we’ve listed (e.g., 09356741, 16236757), this module is the correct replacement once programmed to your VIN.