Restore Your Engine’s Performance and Reliability
Is your 2003-2005 Chevrolet Impala, Monte Carlo, or another GM vehicle giving you headaches? If you’re dealing with a persistent check engine light, rough idling, unexpected stalling, or a frustrating no-start condition, the problem often points directly to a failing Powertrain Control Module (PCM). As the central computer of your vehicle, the PCM manages everything from fuel delivery and spark timing to transmission shifting. When it falters, the entire vehicle’s performance suffers. I’ve seen it hundreds of times in my shop: a good car runs poorly because its electronic brain is failing.
This isn’t just a replacement part; it’s a complete solution. We take the guesswork and high dealership costs out of the equation. This genuine replacement PCM, part number 89017735, arrives at your door pre-programmed with the latest official GM software updates. All we need is your vehicle’s VIN at checkout. This critical step ensures the module communicates perfectly with your car’s specific systems, restoring its original performance and efficiency. By choosing our pre-programmed 2003-2005 Impala PCM, you are bypassing the need for expensive scan tools or a costly visit to the dealer for programming.
From the Diagnostic Bay
I remember a 2004 Monte Carlo that came in with a maddening intermittent stall. The owner had already replaced the fuel pump and crank sensor. No codes were stored. On a long test drive, I finally got it to act up and saw the scanner lose communication with the PCM for a split second right before it died. The internal processor was failing under heat. We installed one of these pre-programmed modules, and the car ran perfectly. It’s often the last thing people suspect, but a faulty PCM can mimic a dozen other problems.
Common Signs of a Failing PCM
If you’re experiencing any of the following, a failing engine computer could be the cause. Confirming the issue with a professional diagnosis is always recommended, but these are classic symptoms I’ve diagnosed for years.
- ✔ Check Engine Light is on with codes like P0601 (Internal Control Module Memory Check Sum Error) or P0606 (PCM Processor Fault).
- ✔ Your vehicle fails to start or starts and then immediately stalls.
- ✔ A noticeable drop in fuel economy.
- ✔ The engine runs rough, misfires, or hesitates during acceleration.
- ✔ Automatic transmission shifts erratically or harshly.
- ✔ Loss of communication with the scan tool.
A Straightforward Guide to Installation
Installing your new 2003-2005 Impala PCM is a manageable job for a DIY enthusiast. The key is taking your time and being careful with the electrical connectors.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post to prevent accidental contact.
- Locate the PCM: On most of these vehicles, the PCM is located in the air filter housing assembly on the driver’s side of the engine compartment. You may need to remove the air filter box lid to access it.
- Disconnect the Connectors: Carefully unlatch and remove the electrical harness connectors from the old module. These connectors have locking tabs; do not force them. Inspect the terminals for any corrosion or damage.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket or housing.
- Install the New Module: Seat the new, pre-programmed PCM into the mounting bracket and secure it.
- Reconnect Everything: Firmly re-attach the electrical connectors until they click into place. Reinstall the air filter housing and reconnect the negative battery terminal.
- Final Steps: Your vehicle may need to complete a security relearn procedure, which typically involves turning the key to the ‘ON’ position for 10-15 minutes. Consult your owner’s manual for specific instructions.
Verified Vehicle Compatibility
This module is a direct replacement for part numbers 89017735, 12583827, and 12583826. It is guaranteed to fit the following models, but always verify your part number or consult with us if you are unsure.
AZTEK 03-05 Electronic Control Module; (LH engine compartment)
BONNEVILLE 04-05 Electronic Control Module; (LH engine compartment), 3.8L
CENTURY 03-05 Electronic Control Module; (LH engine compartment)
GRAND AM 03-05 Electronic Control Module; (LH center dash), 3.4L
GRAND PRIX 03 Electronic Control Module; (LH front engine compartment), 3.1L
IMPALA 03-05 Electronic Control Module; (LH engine compartment), fits 3.4L & 3.8L
LESABRE 04-05 Electronic Control Module; (LH engine compartment)
MALIBU 03 Electronic Control Module; (LH dash)
MONTE CARLO 03-05 Electronic Control Module; (LH engine compartment), fits 3.4L & 3.8L
MONTANA 03-04 Electronic Control Module; (LH engine compartment)
MONTANA 05 Electronic Control Module; (LH engine compartment), Base
PARK AVENUE 04-05 Electronic Control Module; (LH front engine compartment)
RENDEZVOUS 03-05 Electronic Control Module; (LH engine compartment)
SILHOUETTE 03-04 Electronic Control Module; (LH engine compartment)
VENTURE 03-05 Electronic Control Module; (LH engine compartment)
Frequently Asked Questions About This 2003-2005 Impala PCM
Do I need to do any programming after I receive it?
Do I need to do any programming after I receive it?
No. This module comes fully programmed to your vehicle’s VIN with the latest GM software. It is ready for installation right out of the box. A security relearn may be required, which you can typically do yourself.
How do I provide my VIN?
After you complete your purchase, you will need to send us your 17-digit Vehicle Identification Number (VIN). We cannot ship the module until we have this information to program it correctly.
What if my original part number is 12583827 or 12583826?
This part, 89017735, is a fully compatible and updated replacement for those part numbers. It will function identically once programmed for your vehicle.
Is a security relearn procedure difficult?
Not at all. For most GM vehicles of this era, it involves turning the ignition to the ‘ON’ position (without starting the engine) for about 10-15 minutes, then turning it off, and then starting the vehicle. This allows the PCM to recognize your key’s anti-theft signal.
Will this fix my transmission problems?
In many cases, yes. The PCM also controls the transmission’s shift points and line pressure. If your transmission issues are electronic in nature and caused by a faulty PCM, this new module should resolve them. It will not fix internal mechanical failures in the transmission.