Is your Chevrolet Express or GMC Savana van running rough, stalling unexpectedly, or throwing confusing check engine light codes? As a technician with over two decades of experience under the hood, I’ve seen these symptoms countless times. Often, the root cause isn’t a faulty sensor or a bad fuel pump—it’s the vehicle’s brain, the Powertrain Control Module (PCM), that’s failing. This isn’t just an inconvenience; it affects your work, your schedule, and your bottom line. You need a reliable, straightforward fix, and that’s exactly what this is.
This is a direct-fit replacement Powertrain Control Module for a wide range of GM vehicles, including the hard-working 2005-2007 Express 3500 Van. The best part? We take the guesswork and the expensive dealership trip out of the equation. Before we ship it, we program the module with the latest GM software updates, specifically matched to your vehicle using your VIN. This ensures that when it arrives, it’s ready to communicate perfectly with your van’s engine, transmission, and other systems, restoring its original performance and efficiency.
Case Study: The Intermittent No-Start
I remember a 2006 Express 3500 work van that came into my bay. The owner was at his wit’s end. The van would randomly refuse to start, but only after it had been driven for a while and sat for about an hour. No codes, no clear pattern. He’d already replaced the battery and starter. After checking fuel pressure and spark, which were fine during testing, I focused on the PCM. On these vans, heat soak in the engine compartment can expose internal failures in the module. We swapped in a VIN-programmed PCM, and the problem vanished instantly. It wasn’t the fuel system; it was the computer failing when it got hot. This part saved him from chasing a ghost and losing more money on downtime.
Is Your Vehicle Showing These Telltale Signs?
A failing PCM can cause a variety of frustrating issues. If you’re experiencing any of the following, this module is the likely solution your vehicle needs.
- ✔ Unexplained Check Engine Light illumination, often with codes like P0601, P0606, or other communication errors.
- ✔ Engine stalling, stumbling, or hesitating for no apparent reason.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ A sudden drop in fuel economy.
- ✔ Complete no-start or intermittent starting problems.
- ✔ Failure to pass an emissions test due to communication issues with the OBD-II port.
A Straightforward Guide to Installation
Installing your new 2005-2007 Express 3500 PCM is a job most DIYers can handle with basic tools. Following these steps will get you back on the road quickly.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the PCM: On Express and Savana vans, the PCM is typically located in the engine compartment on the driver’s side, near the firewall or airbox. On trucks like the Silverado, it’s often found under the battery tray.
- Disconnect the Connectors: Carefully unclip the wiring harness connectors from the old module. They have locking tabs, so be gentle to avoid damage.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket and remove it from the vehicle.
- Install the New Module: Bolt your new, pre-programmed PCM into place and securely re-attach the wiring harness connectors. You should hear a ‘click’ as they lock.
- Reconnect the Battery: Re-attach the negative battery terminal.
- Perform Security Relearn: In most cases, you will need to perform a security relearn procedure to sync the new PCM with your vehicle’s anti-theft system. This simple procedure typically involves turning the key to the ‘ON’ position for 10-15 minutes and can be done without special tools. Instructions are readily available online for your specific model.
Will This Fit My Vehicle?
This module, part number 12602801, is a direct replacement for service numbers 12589462 and 89017749. It fits a wide array of GM trucks and vans. Please verify your model and year from the list below to ensure compatibility.
- ✔ Chevrolet Express / GMC Savana 1500, 2500, 3500 Vans (2005-2007)
- ✔ Chevrolet Silverado / GMC Sierra 1500, 2500, 3500 Pickups (2005-2007 Classic) – including models with 4.3L and 8.1L gasoline engines.
- ✔ Chevrolet Suburban 2500 / Yukon XL 2500 (2005-2006) – with 8.1L engine.
- ✔ Chevrolet Avalanche 2500 (2005-2006)
- ✔ GMC Safari / Chevrolet Astro (2005)
- ✔ Chevrolet Blazer S10 / GMC Jimmy S15 (2005)
- ✔ Cadillac CTS-V (2004-2005) – check for matching ID number.
Ordering a reliable, correctly programmed 2005-2007 Express 3500 PCM is the most critical step in solving complex electronic issues and restoring your vehicle’s dependability. Let us help you get the job done right the first time.