Restore Peak Performance to Your GM Truck
Is your 2004 GMC Sierra 3500, or another compatible GM vehicle, suffering from perplexing issues like a persistent check engine light, rough idling, poor fuel economy, or even a no-start condition? These are classic signs of a failing Powertrain Control Module (PCM), the central computer that manages your engine and transmission. A faulty PCM can lead to frustrating diagnostic dead-ends and costly, incorrect repairs. This replacement PCM, service number 12586242, is the definitive solution to get your truck running reliably again.
We take the guesswork and hassle out of the repair process. Unlike sourcing a used module from a junkyard that won’t work without expensive dealer programming, this unit comes pre-programmed specifically for your vehicle. Simply provide us with your VIN during checkout, and our technicians will flash the module with the latest, most up-to-date software from General Motors. This ensures perfect compatibility and optimal performance right out of the box.
From the Diagnostic Bay
We recently had a 2004 Silverado 2500 towed in that had its owner completely stumped. The complaint was harsh shifting and intermittent stalling. The owner had already replaced the transmission fluid, filter, and two shift solenoids with no improvement. When we connected our diagnostic scanner, we saw multiple ‘U’ codes, indicating a loss of communication between modules. This immediately pointed us away from the transmission and toward the network controller—the PCM. After confirming power and ground to the module were good, we knew the internal circuitry had failed. We installed one of our VIN-programmed PCMs, performed the quick security relearn procedure, and the truck ran and shifted like it just left the factory. It’s a perfect example of how a faulty PCM can mimic other component failures, costing you time and money.
Common Symptoms of a Failing PCM
- ✔ Persistent Check Engine Light (CEL) with communication codes (e.g., U0100, U0101).
- ✔ Unexplained engine stalling or stumbling, especially when warm.
- ✔ Noticeable decrease in fuel efficiency.
- ✔ Erratic or harsh automatic transmission shifting.
- ✔ Engine misfires that don’t resolve after replacing plugs or coils.
- ✔ The vehicle cranks but will not start (crank-no-start).
- ✔ Inconsistent performance issues that come and go without a clear pattern.
Why This 2004 Sierra 3500 PCM is Your Best Solution
Choosing the right replacement part is crucial for a lasting repair. This module is a direct-fit replacement for a wide range of 2004 GM trucks and SUVs, including the Sierra, Silverado, Tahoe, Suburban, Yukon, Escalade, and more. It is a direct replacement for service numbers 12586242, 19299226, 89017738, and many others. By programming it with your vehicle’s VIN, we ensure all factory settings, including engine and transmission parameters, are correctly calibrated. This eliminates the need for a trip to the dealership, saving you hundreds of dollars in programming fees and labor.
Simple Installation and Security Relearn
Installation is straightforward for any DIY mechanic. After physically swapping the module (typically located under the hood on the driver’s side, near the battery or airbox), you will need to perform a simple security relearn procedure to sync the new PCM with your vehicle’s anti-theft system. This process requires no special tools and takes about 30 minutes.
Security Relearn Procedure:
- With the new PCM installed, insert the key and turn it to the “ON” position (do not start the engine).
- Observe the “Security” or padlock icon on the dashboard. It will be flashing or solid.
- Leave the key in the “ON” position for approximately 10-12 minutes, or until the security light turns off.
- Once the light turns off, turn the key to the “OFF” position for 10 seconds.
- Repeat steps 1-4 two more times for a total of three 10-minute cycles.
- After the third cycle, the vehicle has learned the new PCM, and you can now start the engine.
Frequently Asked Questions
What is VIN programming?
VIN programming is the process of loading your vehicle’s specific software and calibrations onto the PCM. This includes information about your engine size, transmission type, tire size, and other factory options. It is essential for the module to function correctly with your truck. We handle all of this for you before shipping.
Will I need to go to a dealer after installing this PCM?
No. Because we program the module with your VIN and the latest GM software updates, you will not need to visit a dealer for programming. The only post-installation step required is the simple security relearn procedure, which you can do yourself in your driveway.
Is this a simple plug-and-play installation?
Yes, it is designed to be a direct replacement. The connectors will match your factory harness perfectly. After the physical installation, you just need to perform the 30-minute security relearn procedure outlined above, and you’ll be ready to drive.
How do I confirm my old PCM is the problem?
While the symptoms listed are strong indicators, the best way to confirm is with a proper diagnosis. A professional mechanic can check for communication codes (U-codes), verify power and ground at the PCM connector, and rule out other potential issues like wiring problems or faulty sensors.
What information do you need from me after purchase?
After you place your order, you will need to provide us with your vehicle’s 17-digit Vehicle Identification Number (VIN). This is critical for us to program the module correctly for your specific vehicle configuration.