Is Your 2004 Sierra Running Rough? Get a Reliable, Programmed Solution.
As a technician with over two decades of experience, I’ve seen countless GM trucks come into the shop with frustrating, hard-to-diagnose issues. Stalling at stoplights, erratic shifting, a persistent check engine light, or a complete no-start condition can often point directly to a failing Powertrain Control Module (PCM). Your 2004 Sierra 1500 is a workhorse, but when its electronic brain falters, it can bring your entire day to a halt.
This isn’t just a replacement part; it’s a direct-fit, fully programmed solution. We take your vehicle’s VIN and flash this module with the latest, most stable software from GM. This means it arrives at your door ready to install, with no expensive trip to the dealership for programming required. It directly replaces original part numbers 12586243 and 89017739, restoring your truck’s factory performance and reliability.
Common Symptoms of a Failing 2004 Sierra 1500 PCM
If you’re experiencing any of the following, a faulty PCM is a likely culprit. I’ve personally traced these symptoms back to the PCM on hundreds of GM vehicles from this era.
- โ Check Engine Light (CEL) with communication-related trouble codes.
- โ Engine stalling or shutting off while driving.
- โ Harsh or unpredictable transmission shifting.
- โ A no-start condition where the engine cranks but won’t fire.
- โ Poor fuel economy and a noticeable loss of power.
- โ Seemingly random electrical issues or warning lights.
Expert Pro Tip: Check Your Grounds Before You Replace!
Before you condemn your PCM, take 10 minutes to inspect the main engine-to-chassis ground strap. On these GMT800 trucks, it’s often located near the front of the passenger side cylinder head. Over the years, this strap can corrode, causing voltage drops that mimic PCM failure. A customer’s 2004 Sierra 1500 came in last month with a no-start issue everyone else had diagnosed as a bad PCM. A simple wire brush cleaning of the ground connection and a new bolt had it running perfectly. Always check the simple things first!
Plug-and-Play Installation: No Dealer Visit Required
Installing your new PCM is a straightforward process you can do in your own driveway. This module for your Sierra 1500 is located on the driver’s side, under the battery tray. Just follow these steps:
- Safety First: Disconnect the negative terminal from your truck’s battery.
- Access the Module: Remove the battery and the battery tray to gain clear access to the old PCM.
- Disconnect the Old PCM: Carefully unplug the electrical connectors. These have locking tabs, so don’t force them. Unbolt the module from its bracket.
- Install the New PCM: Bolt your new, pre-programmed module into place. Reconnect the electrical connectors, ensuring they click securely.
- Reassemble: Reinstall the battery tray and the battery. Reconnect the negative battery terminal.
- Security Relearn: You will need to perform a simple security relearn procedure. Turn the key to the ‘ON’ position for 10-15 minutes, then ‘OFF’ for 10 seconds. Repeat this cycle three times. On the fourth try, the truck should start, and the security light will be off.
By providing your VIN at checkout, you ensure this module is a perfect match for your truck’s specific configuration, saving you hundreds of dollars and the hassle of a dealer visit. Get your Sierra back to work with a solution you can trust.