Is Your 2003 Express 3500 Running Rough, Stalling, or Not Starting At All?
As a technician with over two decades of experience, I know that a failing Powertrain Control Module (PCM) can bring your workhorse van to a dead stop. If you’re dealing with frustrating issues like a persistent check engine light, erratic transmission shifting, poor fuel economy, or a complete no-start condition, the problem often points directly to the vehicle’s computer. The 2003 Express 3500 PCM is the central command center, and when it fails, it creates chaos for the entire powertrain.
Forget the hassle and high cost of a dealership visit. This is a direct-fit replacement PCM, part number 12576106, that arrives at your door fully programmed to your van’s specific Vehicle Identification Number (VIN). We load the latest, most stable software from GM, ensuring optimal performance and compatibility right out of the box.
From My Shop to Your Driveway
“A contractor’s 2003 Express 3500 was towed in last week. It would crank endlessly but never fire up, and the security light was flashing. My initial scan showed a ‘No Communication’ error with the PCM. After confirming the module had good power and ground at the connectors, I knew the internal processor had failedโa common issue I’ve seen on hundreds of these GM vans. We installed one of our pre-programmed modules, performed the security relearn, and he was back on the road to his next job in under an hour. That’s the difference the right part makes.”
Your Plug-and-Play Solution
This isn’t just a part; it’s a complete solution designed to get you back to work with minimal downtime. Simply provide us with your VIN during checkout, and we handle the complex programming for you.
- โ VIN-Programmed for You: Arrives ready for installation, flashed with the latest GM calibration for your specific vehicle.
- โ No Dealer Required: Save hundreds of dollars and avoid the inconvenience of towing your van to a dealership for programming.
- โ Solves Common Issues: Directly addresses symptoms like harsh shifting, no-start, stalling, false sensor codes, and communication errors.
- โ Direct-Fit Guarantee: Engineered to match the original form and function, ensuring a perfect fit and connection. This module is a direct replacement for service numbers including 12576106, 12581565, 12570557, and 89017733.
Easy Installation Guide
Replacing the PCM on your Express van is straightforward. In most cases, it’s located in the engine compartment on the driver’s side. Follow these steps for a successful installation:
- Safety First: Disconnect the negative terminal from your vehicle’s battery and wait 10-15 minutes to allow all system capacitors to discharge fully.
- Locate the PCM: Find the existing module in the LH rear of the engine compartment.
- Disconnect Connectors: Carefully unclip and remove the wiring harness connectors from the old PCM. Inspect them for any corrosion or bent pins.
- Remove Old Module: Unbolt the old PCM from its mounting bracket and remove it from the vehicle.
- Install New Module: Mount the new, programmed PCM in place and securely tighten the bolts.
- Reconnect Harness: Plug the wiring harness connectors firmly into the new module until they click.
- Reconnect Battery: Reattach the negative battery terminal.
- Perform Security Relearn: You will need to perform a simple key-cycle security relearn procedure. This takes about 30 minutes and does not require any special tools. Instructions will be included.
Expert Pro Tip: Before installing your new PCM, take a moment to inspect the main wiring harness that runs near the driver’s side exhaust manifold. Over time, the plastic loom can become brittle, and wires can chafe against the frame or engine block. This can cause intermittent shorts that damage the PCM drivers. A quick inspection and some zip ties or protective wrap can prevent a repeat failure.
Guaranteed Compatibility
This module is the correct replacement for a wide range of 2003-2004 GM trucks, vans, and SUVs. It is a direct replacement for multiple service numbers, including: 12581565, IS 8125815650, 12570557, 12570558, 12576106, 12576869, 12578127, 8125781270, 88864822, and 89017733. It fits vehicles like the Silverado, Sierra, Suburban, Yukon, Avalanche, S10, and more. Please verify your vehicle in the fitment chart to ensure compatibility.