Is Your 2004 Express 3500 Running Rough?
If your workhorse van is suddenly stalling, shifting erratically, or displaying a persistent Check Engine Light, a failing Powertrain Control Module (PCM) is a likely culprit. As the brain of your vehicle’s engine and transmission, when the PCM starts to fail, it can cause a host of frustrating and seemingly unrelated problems. You need a solution that’s reliable, fast, and doesn’t require an expensive trip to the dealership.
This is a direct-fit replacement Engine Control Module (also known as an ECM or PCM) for your 2004 GM vehicle, bearing part number 89017739 (also compatible with 12586243). The most critical service we provide is that we program the module to your vehicle’s specific VIN before it ships. This means it arrives ready to install, loaded with the latest GM software updates to ensure optimal performance and communication with all other modules in your van.
Common Symptoms of a Failing GM PCM:
- โ Unexplained Check Engine Light (with codes pointing to module communication or sensor circuits)
- โ Rough or unstable idle
- โ Vehicle stalling for no reason
- โ Poor fuel economy
- โ Harsh or delayed transmission shifting
- โ Engine misfires or loss of power
- โ Complete no-start condition
From the Shop Floor: A Real-World Diagnosis
“A customer’s 2004 Savana 3500 (which uses the same platform as the Express) came into my shop last month with a complaint of intermittent stalling and a ‘Service Engine Soon’ light. The owner had already replaced the fuel pump, thinking it was a fuel delivery issue. My professional scan tool, however, showed U-series communication codes, indicating the PCM wasn’t talking correctly to the other modules. After confirming the power and ground circuits to the PCM were solid, we installed a VIN-programmed module just like this one. The communication codes vanished, and the van has been running flawlessly for his plumbing business ever since. It saved him from chasing phantom issues and spending more money on unnecessary parts.”
Plug-and-Play Installation for Your 2004 Express 3500 PCM
Installing your new module is a straightforward process that you can do in your own driveway. No dealer visit is required for programming. Just provide us with your VIN during checkout, and we handle the rest.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post.
- Locate the PCM: On the 2004 Express 3500, the PCM is typically located in the left-hand (driver’s side) rear of the engine compartment.
- Disconnect the Harnesses: Carefully release the locking tabs on the electrical connectors and pull them straight out from the module. Inspect the connectors for any signs of corrosion or bent pins.
- Remove the Old Module: Unbolt the PCM from its mounting bracket.
- Install the New Module: Bolt your new, pre-programmed PCM into place.
- Reconnect Everything: Firmly plug the electrical harnesses back into the new module until they click into place. Reconnect your negative battery terminal.
- Final Step: In some cases, a security relearn procedure may be necessary, which typically involves cycling the key. Your vehicle’s service manual will have the specific, simple steps if required.
By ordering this module, you’re not just buying a part; you’re getting a complete, ready-to-install solution that restores your vehicle’s reliability and performance. Get your van back to work without the hassle and high cost of dealer service.