Is Your 2004 Sierra 1500 Running Rough or Not Starting?
If you’re dealing with a persistent check engine light, erratic engine behavior, or a truck that just won’t start, a failing Powertrain Control Module (PCM) is often the culprit. As the brain of your truck’s engine, when the PCM goes bad, it can cause a cascade of frustrating and hard-to-diagnose issues. I’ve seen it countless times in my 20+ years on the shop floor: perfectly good sensors and components get replaced, only for the problem to remain because the original PCM was the root cause.
This isn’t just a replacement part; it’s a direct solution. We take a quality-tested PCM, part number 89017739, and program it specifically to your truck’s 17-digit Vehicle Identification Number (VIN). This ensures it has the latest GM software updates and communicates flawlessly with your vehicle’s existing systems, just like a new module from the factory, but without the dealership price tag and hassle.
Get Back on the Road with Confidence
A faulty PCM can manifest in many ways. If you’re experiencing any of the following, it’s a strong indicator that your engine computer needs attention:
- โ Unexplained Check Engine Light (especially with communication codes like P0601 or P0606)
- โ Engine stalling, stumbling, or misfiring
- โ Complete no-start condition where the engine cranks but won’t fire
- โ Poor fuel economy and decreased engine power
- โ Harsh or incorrect automatic transmission shifting
- โ Failure to pass an emissions test
Real-World Diagnosis: A Technician’s Experience
“A customer’s 2004 Sierra 1500 with the 4.3L V6 came into my shop last month. It had a persistent P0601 (Internal Control Module Memory Check Sum Error) code that wouldn’t clear, and the truck would intermittently stall at red lights. After verifying the grounds and power feeds to the PCM were solidโa critical first stepโwe knew the module itself had failed internally. Swapping in a pre-programmed unit like this one is the most efficient repair. It had him back on the road with a smooth-running truck in under an hour, with no further issues.”
Easy Installation for Your 2004 Sierra 1500 PCM
One of the biggest benefits of our service is that this module arrives ready to install. No need to have your truck towed to a dealer for expensive programming. For your 2004 Sierra 1500, the PCM is typically located in the engine bay, on the driver’s side, under or near the battery. The process is straightforward for a DIYer with basic tools.
- Safety First: Disconnect the negative terminal from your truck’s battery and wait at least 15 minutes for the systems to fully power down.
- Locate the PCM: Find the module on the driver’s side (LH) of the engine compartment, usually under a plastic cover near the battery tray.
- Disconnect the Harnesses: Carefully unplug the electrical connectors from the old PCM. They have locking tabs that need to be released. Inspect the connectors for any corrosion or bent pins.
- Remove the Old Module: Unbolt the old PCM from its mounting bracket.
- Install the New Module: Bolt your new, pre-programmed PCM into place.
- Reconnect Everything: Securely plug the electrical harnesses into the new module. You should hear a ‘click’ as they lock. Reconnect the negative battery terminal.
- Perform Security Relearn (If Necessary): In some cases, a simple 10-15 minute security relearn procedure is needed. This involves turning the key to the ‘ON’ position for 10 minutes, then ‘OFF’, and repeating two more times. Your truck should then start and run correctly.
How It Works: VIN Programming is Key
After you complete your purchase, simply send us your truck’s VIN. Our technicians will use this number to access the correct GM software and flash it directly onto the module. This ensures all factory settings for your specific engine, transmission, and options are loaded correctly. This module is a direct replacement for part numbers 89017739 and 12586243, and while it fits a wide range of GM vehicles from 2004, this service guarantees it’s a perfect electronic match for your Sierra 1500.