Is Your 2003 Blazer, Jimmy, or S10 Running Rough?
If you’re dealing with frustrating issues like intermittent stalling, a no-start condition that leaves you stranded, erratic transmission shifting, or a check engine light that won’t go away, the problem often points directly to a failing Powertrain Control Module (PCM). As the central computer of your vehicle, when the PCM starts to fail, it can create a cascade of confusing and unpredictable symptoms. I’ve seen it hundreds of times in the shop: owners replace sensor after sensor, only to find the root cause was the vehicle’s brain all along.
From the Shop Floor: “A customer’s 2003 GMC Jimmy S15 came in last week with these exact symptoms. It would die at stoplights intermittently, and he was getting random communication error codes that made no sense. We checked all the usual suspectsโfuel pressure, ignition system, groundsโand everything seemed fine. After connecting our diagnostic scanner and seeing inconsistent data streams from the PCM, we knew where the problem was. A failing module was sending bad commands, causing chaos. Replacing it with a properly programmed unit solved every single issue instantly.”
The Direct Solution: A VIN-Programmed 2003 Blazer S10 PCM
This isn’t just a replacement part; it’s a complete, ready-to-install solution. We take a genuine OEM-spec PCM and flash it with the latest GM-certified software calibration specifically for your vehicle’s VIN. This critical step ensures all factory settings for the engine, transmission, and emissions systems are perfectly matched to your Blazer or Jimmy, restoring its original performance and reliability.
- โ Eliminate Guesswork: Solves common issues like harsh shifting, poor fuel economy, stalling, and false error codes.
- โ VIN-Specific Programming: We program the module to your exact vehicle, ensuring 100% compatibility and function.
- โ Latest GM Updates: Your module arrives with the most current software, often fixing factory bugs you didn’t even know you had.
- โ No Dealer Required: This module is sent to you ready for installation, saving you the time and high cost of a dealership programming appointment.
Simple, Plug-and-Play Installation
You don’t need to be a master technician to get your truck back on the road. The PCM on the 2003 Blazer S10 / Jimmy S15 is located in the right-hand (passenger side) front of the engine compartment.
- Safety First: Disconnect the negative terminal from your vehicle’s battery.
- Locate the PCM: Find the module on the passenger side of the engine bay, typically near the firewall or inner fender.
- Disconnect Connectors: Carefully unclip the electrical wiring harnesses. They have locking tabs, so be gentle to avoid damage.
- Remove the Old Module: Unbolt the PCM from its mounting bracket.
- Install the New Module: Bolt your new, pre-programmed PCM into place and securely reconnect the wiring harnesses.
- Reconnect Battery: Re-attach the negative battery terminal. Your vehicle is now ready to start.
Expert Pro Tip: Before installing your new PCM, take a moment to inspect and clean the main engine and chassis ground connections. On these GM trucks, a corroded or loose ground strap (especially the one from the engine block to the frame) can cause voltage irregularities that damage sensitive electronics. A few minutes with a wire brush can prevent a costly repeat failure.
Guaranteed Compatibility
This module is a direct replacement for a wide range of GM trucks and vans from this era. Please provide your VIN upon purchase to ensure perfect programming. This unit is compatible with the following service part numbers:
Service Numbers: 12581565, 8125815650, 12570557, 12570558, 12576106, 12576869, 12578127, 8125781270, 88864822, 89017733
Vehicle Fitment List:
This part fits numerous 2003-2004 GM models, including the Chevrolet Blazer S10, GMC Jimmy S15, S10/Sonoma, Silverado, Sierra, Express, Savana, Astro, Safari, Avalanche, Suburban, Yukon, and the 2004 Cadillac CTS and Corvette with matching ID. Please verify your part number or contact us with your VIN to confirm fitment.