Restore Your Workhorse: The Reliable Fix for Your GM Van or Truck
As a mechanic with two decades of experience under the hood, I’ve seen firsthand how a failing Powertrain Control Module (PCM) can bring a dependable work vehicle like the 2005-2007 Express 3500 Van to a grinding halt. When your van’s ‘brain’ starts to fail, it can cause a cascade of frustrating issues, from poor fuel economy and erratic shifting to a no-start condition that costs you time and money. This isn’t just an inconvenience; for a business owner, it’s a direct hit to the bottom line. That’s why we offer a straightforward, reliable solution.
This isn’t just a replacement part; it’s a complete service. We take a genuine GM PCM, compatible with part numbers 12589462, 12602801, and 89017749, and professionally program it to your vehicle’s specific Vehicle Identification Number (VIN). This ensures that all factory settings for your engine, transmission, and emissions systems are perfectly calibrated. We load the newest, most stable software updates from GM, which often resolve underlying issues the original software had. The result is a dependable Express 3500 Van PCM that restores the performance and reliability you count on every day.
A Technician’s Notebook: The Intermittent Stall
I once had a local delivery company bring in their ’06 Savana 3500. The driver complained of random stalling at stoplights, but with no consistent Check Engine Light. We checked fuel pressure, ignition components, and sensors—all tested fine. The problem was maddeningly intermittent. After hooking up a scope and monitoring the PCM’s 5-volt reference signal on a long test drive, we finally caught it: a momentary, sharp voltage drop just before a stall. The PCM’s internal voltage regulator was failing under heat soak. Replacing the module with a VIN-programmed unit like this one solved the problem permanently. These intermittent electrical faults are a classic sign of a failing PCM.
Is Your Vehicle Showing These Symptoms?
- ✔ Unexplained Check Engine Light with codes like P0601 (Internal Control Module Memory Check Sum Error), P0606 (PCM Processor Fault), or U0100 (Lost Communication with ECM/PCM).
- ✔ The engine cranks but refuses to start.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ A noticeable, sudden drop in fuel economy.
- ✔ Intermittent stalling, especially after the engine has warmed up.
- ✔ Misfires or rough idling that can’t be traced to plugs, coils, or injectors.
A Straightforward Guide to Your Van’s PCM Installation
Replacing the Express 3500 Van PCM is a job most DIYers can handle. For these vans, the module is typically located in the engine compartment on the driver’s side.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait at least 10 minutes for the system capacitors to discharge.
- Locate the PCM: On your Express or Savana Van, find the module in the left-hand (driver’s side) rear of the engine compartment.
- Disconnect the Connectors: Carefully unlatch and remove the electrical wiring harness connectors. Inspect them for any corrosion or damage.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket. Keep the hardware as you will need it for the new module.
- Install the New PCM: Mount your new, pre-programmed module onto the bracket and securely fasten it.
- Reconnect Everything: Plug the wiring harnesses back into the new PCM, ensuring they click securely into place. Reconnect the negative battery terminal.
- Final Step: In some cases, a security relearn procedure may be necessary, which can typically be done without special tools by cycling the key. Your vehicle’s service manual will have the specific steps.
Will This Fit My Vehicle?
We guarantee this module is compatible with a wide range of GM vehicles. Please match your part number (12589462, 12602801, or 89017749) or verify your vehicle is on the list below. This is a direct-fit solution for the following models and years:
AVALANCHE 2500 (05-06), ASTRO (05), BLAZER S10 (05), EXPRESS 1500/2500/3500 (05-07), SILVERADO 1500/2500/3500 (05-07, including Classic), SUBURBAN 2500 (05-06)
GMC:
JIMMY S15 (05), SAFARI (05), SAVANA 1500/2500/3500 (05-07), SIERRA 1500/2500/3500 (05-07, including Classic), YUKON XL 2500 (05-06)
Cadillac:
CTS (04-05, V-Series with specific IDs)
Frequently Asked Questions About This PCM
Frequently Asked Questions
Why do you need my VIN?
Your VIN is essential. It allows us to program the PCM with the exact software calibration for your vehicle’s engine, transmission, and factory options. This ensures seamless communication between all modules and proper vehicle operation, avoiding a costly trip to the dealer.
Is this a simple plug-and-play installation?
Yes, for most vehicles. Because the module arrives programmed to your VIN, you can typically install it and start the vehicle. Some models may require a simple key-cycle security relearn procedure, which does not require special tools.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the old PCM (like codes P0601-P0606), then yes, this module will resolve the issue. However, if the light is on for another reason (e.g., a bad oxygen sensor), you will still need to fix that separate problem.
What if my part number isn’t an exact match?
This module is a direct replacement for several part numbers, including 12589462, 12602801, and 89017749. As long as your vehicle is on our compatibility list, this module will function correctly once programmed to your VIN.