Restore Peak Performance to Your GM Vehicle
Is your 2003 Chevy Express 3500, or another compatible GM truck or van, suffering from frustrating and costly issues? Symptoms like a persistent check engine light, erratic shifting, a no-start condition, or poor fuel economy often point directly to a failing Powertrain Control Module (PCM). This isn’t just an inconvenience; it’s a critical failure that can leave your work van or daily driver stranded. This replacement PCM, part number IS 8125815650, is the definitive solution to get you back on the road with confidence.
We take the guesswork and dealer hassle out of the equation. Before this module ships, we program it using your vehicle’s specific Vehicle Identification Number (VIN). This ensures it’s loaded with the latest GM factory software updates for your exact model, resolving software bugs and improving operational efficiency. Itโs a true plug-and-play solution designed for a straightforward installation.
Common Symptoms of a Failing PCM:
- โ Check Engine Light (CEL) is illuminated with various communication or sensor codes.
- โ The engine cranks but refuses to start.
- โ Harsh or unpredictable automatic transmission shifting.
- โ Noticeable decrease in fuel mileage.
- โ Stalling, stumbling, or misfiring while driving.
From the Shop Floor: A Real-World Diagnosis
“A customer’s 2003 Express 3500 work van came in last week with a baffling intermittent no-start. It would run fine for days, then refuse to fire up, leaving his crew stranded. We checked the fuel pump, ignition system, and all the usual suspects, but everything tested good. After hooking up our professional scan tool, we noticed the PCM would occasionally lose communication with the other modules right when the fault occurred. On these GM vans, years of engine heat and vibration can cause microscopic cracks in the PCM’s internal circuit board. We installed one of our VIN-programmed PCMs, and the van has been starting reliably ever since. It’s a common failure point I’ve seen dozens of times on this platform.”
Why Choose Our 2003 Express 3500 PCM?
This isn’t just a replacement part; it’s a complete service. By providing us with your VIN upon purchase, you receive a module that is perfectly matched to your vehicle’s factory specifications and loaded with the most current software available from GM. This process is critical for proper engine, transmission, and emissions system operation.
Easy Installation Guide
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post.
- Locate the PCM: On most 2003 Express/Savana vans, the PCM is located in the engine compartment on the driver’s side, near the master cylinder. On trucks, it’s often under the battery tray. Always verify the location for your specific model.
- Disconnect the Connectors: Carefully unclip and remove the electrical harness connectors from the old PCM. Inspect the pins on the harness side for any corrosion or damage. Clean them with a dedicated electronics cleaner if necessary.
- Swap the Module: Unbolt and remove the old PCM. Mount the new module securely in its place.
- Reconnect Everything: Firmly plug the harness connectors into the new PCM until they click into place. Reconnect the negative battery terminal.
- Final Steps: Your vehicle is now ready to start. In some cases, a security relearn procedure may be required, which can typically be done without special tools. Instructions are readily available online for your specific model.
Guaranteed Compatibility
This module is a direct replacement for a wide range of GM vehicles and service numbers. Please verify your part number or vehicle in the list below.
Replaces Service Numbers: 12581565, IS 8125815650, 12570557, 12570558, 12576106, 12576869, 12578127, 8125781270, 88864822, 89017733
Fitment Details:
- ASTRO 03: Electronic Control Module; (LH front by battery)
- AVALANCHE 2500 03: Electronic Control Module; (LH front under battery)
- BLAZER S10/JIMMY S15 03: Electronic Control Module; (RH front engine compartment)
- CTS 04: Electronic Control Module; (RH engine compartment), Base, ID 12581565
- CORVETTE 04: Electronic Control Module; (RH engine compartment), ID 12581565
- EXPRESS/SAVANA 1500 VAN 03: Electronic Control Module; (LH rear engine compartment)
- EXPRESS/SAVANA 2500 VAN 03: Engine Computer (LH rear engine compartment)
- EXPRESS/SAVANA 3500 VAN 03: Electronic Control Module; (LH rear engine compartment)
- S10/S15/SONOMA 03: Electronic Control Module; (RH front engine compartment), 4.3L
- SAFARI (GMC) 03: Electronic Control Module; (LH front by battery)
- SIERRA 1500 PICKUP 03: Electronic Control Module; (LH front under battery), w/4.3L
- SIERRA/SILVERADO 2500 PICKUP 03: Powertrain Control Module; (LH front under battery), gasoline, 8.1L
- SIERRA/SILVERADO 3500 PICKUP 03: Engine Control Module; (LH front under battery), gasoline, 8.1L
- SUBURBAN 2500 03: Electronic Control Module; (LH front under battery), 8.1L
- YUKON XL 2500 03: Electronic Control Module; (LH front under battery), 8.1L