Programmed 2003 Avalanche 2500 PCM | ECM Engine Computer 12576869

Restore Peak Performance to Your GM Truck or Van

Is your 2003 Chevrolet Avalanche 2500 or other GM vehicle suffering from frustrating issues like a persistent check engine light, poor fuel mileage, erratic shifting, or a no-start condition? These are classic signs of a failing Powertrain Control Module (PCM), the central computer that manages your engine and transmission. Driving with a faulty PCM can lead to further component damage and leave you stranded. This isn’t just a part; it’s the solution to getting your vehicle running reliably again.

We take the guesswork and hassle out of the repair. This replacement PCM, part number 12576869, arrives at your door pre-programmed with the latest official GM software updates. All we need is your vehicle’s 17-digit VIN during checkout. This critical step ensures the module is a perfect match for your vehicle’s specific configuration, eliminating the need for an expensive trip to the dealership for programming. It’s a direct-fit, effective solution for both seasoned mechanics and first-time DIYers.

Is Your Vehicle Showing These Symptoms?

A failing engine computer can cause a wide range of problems. If you’re experiencing any of the following, a faulty PCM could be the culprit:

• ✔ Check Engine Light is illuminated with codes like P0601 (Internal Control Module Memory Check Sum Error), P0606 (PCM Processor Fault), or other communication errors.
• ✔ The engine cranks but refuses to start.
• ✔ Noticeable decrease in fuel economy.
• ✔ The transmission shifts harshly, erratically, or at the wrong times.
• ✔ Unexplained engine stalling or rough idling.
• ✔ Failure to pass an emissions inspection.

A Straightforward Guide to Installation

Replacing the PCM on most of these GM trucks and vans is a manageable job. With this pre-programmed module, you avoid the most complicated step. Always consult a vehicle-specific repair manual if you are unsure.

1. Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post to prevent accidental reconnection.
2. Locate the PCM: On most trucks (like the Avalanche, Silverado, Sierra), the PCM is located on the driver’s side of the engine bay, under or near the battery tray. On vans (Express, Savana), it’s typically in the LH rear of the engine compartment.
3. Disconnect the Connectors: Carefully unlatch and remove the electrical wiring harness connectors from the old module. These connectors have locking tabs that must be released before pulling. Inspect them for any corrosion or damage.
4. Remove the Old Module: Unbolt the PCM from its mounting bracket. It’s typically held in place by a few small bolts.
5. Install the New Module: Mount your new, pre-programmed PCM onto the bracket and securely fasten the bolts.
6. Reconnect Everything: Firmly plug the wiring harness connectors into the new module until they click into place. Reconnect the negative battery terminal.
7. Perform Security Relearn (If Necessary): In many cases, you may need to perform a simple security relearn procedure, which typically involves turning the key to the ‘ON’ position for 10-15 minutes. This allows the new PCM to recognize your vehicle’s anti-theft system.

Verified Vehicle Compatibility

This module is a direct replacement for a wide range of GM vehicles. Please verify your model and engine combination below. This part is compatible with service numbers: 12581565, 12570557, 12570558, 12576106, 12576869, 12578127, 88864822, and 89017733.

• 2003 Avalanche 2500 (LH front under battery)
• 2003-2004 Cadillac CTS (Base, ID 12581565)
• 2004 Corvette (ID 12581565)
• 2003 Chevy/GMC Trucks (Gasoline):
  • Silverado/Sierra 1500 (4.3L)
  • Silverado/Sierra 2500 (8.1L)
  • Silverado/Sierra 3500 (8.1L)
  • Suburban/Yukon XL 2500 (8.1L)
• 2003 Chevy/GMC Vans:
  • Express/Savana 1500, 2500, 3500
  • Astro/Safari
• 2003 S-Series Trucks/SUVs:
  • S10/S15/Sonoma (4.3L)
  • Blazer S10/Jimmy S15

Frequently Asked Questions About This 2003 Avalanche 2500 PCM