Bring Your GM Truck Back to Life
Is your 2004 Silverado, Sierra, Tahoe, or other GM vehicle suffering from frustrating and unpredictable issues? A failing Powertrain Control Module (PCM) can be the hidden culprit behind a host of problems, turning your dependable workhorse into a source of constant worry. This genuine GM service PCM, part number 12586242, is the definitive solution to restore your vehicle’s engine performance, transmission shifting, and overall reliability. We take the guesswork out of the repair by pre-programming the module to your specific Vehicle Identification Number (VIN) with the latest factory software updates. This ensures a seamless integration, getting you back on the road with the confidence and peace of mind you deserve.
Warning Signs Your PCM is Failing
A faulty engine computer can manifest in numerous ways. If you’re experiencing any of the following, it’s a strong indicator that your 2004 GM Truck PCM may need replacement:
- ✔ Unexplained Check Engine Light illumination, often with communication-related DTCs like P0601, P0602, or P0606.
- ✔ Harsh, erratic, or delayed transmission shifting.
- ✔ Sudden engine stalling or difficulty starting, even with a good battery and starter.
- ✔ A noticeable drop in fuel economy without any change in driving habits.
- ✔ Misfires or rough idling that can’t be traced to spark plugs, coils, or injectors.
- ✔ Other electronic systems acting erratically due to network communication failures.
Expert Diagnostic Tip
Before condemning your PCM, always perform a thorough check of your vehicle’s battery, alternator, and all primary ground connections. A weak battery or a corroded ground strap can cause low voltage issues that mimic PCM failure. A simple voltage drop test on the main power and ground wires to the computer can save you from a costly misdiagnosis. A healthy electrical foundation is critical for any control module to function correctly.
Guided Installation to Restore Your Ride
Replacing the PCM is a straightforward job that a confident DIYer can tackle. Follow these steps for a successful installation:
- Safety First: Begin by disconnecting the negative terminal of your vehicle’s battery to prevent any electrical shorts.
- Locate the Module: On most trucks (Silverado, Sierra, Escalade), the PCM is located under the battery tray on the driver’s side. On SUVs (Tahoe, Envoy, Trailblazer), it’s typically found next to the airbox in the engine bay.
- Disconnect and Remove: Carefully unplug the electrical connectors. They have locking tabs that need to be released. Once disconnected, unbolt the old PCM from its mounting bracket and remove it from the vehicle.
- Install the New PCM: Mount your new, pre-programmed PCM securely onto the bracket. Reconnect the electrical harnesses, ensuring they click firmly into place.
- Reconnect Power: Reattach the negative battery terminal and tighten it securely.
- Perform Security Relearn: Your vehicle’s anti-theft system may need to be relearned to the new PCM. This procedure typically involves turning the key to the ‘ON’ position for 10-15 minutes, then ‘OFF’, and repeating two more times. Consult your owner’s manual for the specific procedure for your model. This is a crucial step for the vehicle to start.
Tailored Fit for Your GM Vehicle
This 2004 GM Truck PCM is a direct-fit replacement for a wide range of models equipped with the 5.3L and 6.0L engines. Please verify your service number matches one of the following: 12586242, 19299226, 89017738, YFKD, YFKF, YFKH, YFKJ, YFKX, YFXL, YFXM, YFXN, YFXP, or YHTN.
ENVOY XL 04 5.3L (next to air box), ID YHTN, YFKH, YFKX, YFXL, YFKD, YFXM, YFXP, YFKF, YFKJ, YFXN
ENVOY XUV 04 5.3L (next to air box), ID YFKH, YFXL, YFXP, YHTN, YFKJ, YFXM, YFKX, YFKD, YFKF, YFXN
ESCALADE & ESV & EXT 04 (LH front under battery), ID 12586242
HUMMER H2 04 (LH front under battery), SUT
ISUZU ASCENDER 04 (LH engine), 5.3L
RAINIER 04 5.3L (next to air box), ID YFXL, YFKJ, YFXM, YFXN, YFXP, YHTN, YFKD, YFKH, YFKF, YFKX
SIERRA 1500 PICKUP 04 (LH front under battery), w/o hybrid; w/o 4.3L; ID 12586242
SIERRA 2500 & 3500 PICKUP 04 (LH front under battery), gasoline, 6.0L, ID 12586242
SIERRA DENALI 04 (LH front under battery), ID 12586242
SILVERADO 1500 PICKUP 04 (LH front under battery), w/o hybrid; w/o 4.3L; ID 12586242
SILVERADO 2500 & 3500 PICKUP 04 (LH front under battery), gasoline, 6.0L, ID 12586242
SSR 04 (next to air box), ID YHTN, YFKD, YFKX, YFXL, YFKF, YFKH, YFXM, YFXN, YFXP, YFKJ
SUBURBAN 1500 & 2500 04 (LH front under battery), ID 12586242
TAHOE 04 (LH front under battery), ID 12586242
TRAILBLAZER EXT 04 5.3L (next to air box), ID YFKX, YFXP, YFXN, YHTN, YFKD, YFXL, YFKJ, YFKF, YFKH, YFXM
YUKON & YUKON XL 1500 & 2500 04 (LH front under battery), ID 12586242
Frequently Asked Questions
What is a PCM and why is it so important?
The Powertrain Control Module is the central computer of your vehicle. It controls everything from fuel injection and ignition timing to transmission shift points and emissions systems. A properly functioning PCM is essential for a smooth, efficient, and reliable driving experience.
Is this module truly plug-and-play?
Because we program it to your vehicle’s specific VIN, it is designed for a straightforward installation. However, you will need to perform the vehicle’s security relearn procedure after installation, which is a simple process that pairs the new module to your keys. This is a necessary security step for the vehicle to start.
How do I provide my VIN for programming?
After you complete your purchase, simply reply to your order confirmation email with your 17-digit VIN. You can also add it to the notes section during checkout. We cannot ship your part until we receive the VIN.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the old PCM (like a P0601 code), this new module will resolve the issue. However, if the light is on due to a faulty sensor or other component, that separate issue will still need to be addressed. This part fixes the computer, not external sensors.
Is there a warranty included with this part?
Yes, all of our pre-programmed modules come with a comprehensive warranty. Please see the warranty tab on this page for complete details and feel confident in your purchase.