Is Your 2004 GM Truck or SUV Running Poorly?
If you’re dealing with a persistent check engine light, erratic engine behavior, stalling, or a no-start condition in your 2004 GMC Sierra, Chevrolet Silverado, or other compatible GM vehicle, a failing Powertrain Control Module (PCM) is a likely culprit. The PCM is the central computer of your vehicle, responsible for managing everything from fuel injection and ignition timing to transmission shifting and emissions controls. When it fails, it can cause a wide range of frustrating and difficult-to-diagnose problems.
This listing is for a direct-fit replacement PCM, service number 12586242. We take the guesswork out of the repair by programming the module specifically for your vehicle using the VIN you provide. This ensures that all factory settings, security information, and operational parameters are a perfect match, making installation as simple as possible.
From the Diagnostic Bay
We had a 2004 Tahoe come in with a complaint of intermittent stalling and a check engine light for a random misfire. The owner had already replaced the spark plugs, wires, and even a coil pack with no success. After hooking up our scanner, we noticed the data stream for the crank position sensor was dropping out sporadically. While the sensor itself tested fine, a deeper look at the wiring diagram showed the signal goes directly to the PCM. We scoped the signal at the PCM connector and confirmed it was clean. The issue was internal; the PCM’s driver circuit for that sensor was failing. A new, programmed PCM like this one solved the problem instantly, saving the customer from throwing more parts at a problem that wasn’t there.
Symptoms of a Failing 2004 Sierra 1500 PCM
A faulty engine computer can manifest in numerous ways. If you’re experiencing any of the following, it might be time to consider a replacement:
- ✔ Check Engine Light: The most common symptom, often with codes related to sensor circuits (P0100-P0600 series) or communication errors (U-codes).
- ✔ Engine Stalling or Misfiring: The engine may stall unexpectedly, run rough, or misfire as the PCM struggles to control spark and fuel.
- ✔ Poor Fuel Economy: Incorrect fuel mixture calculations can lead to a sudden and significant drop in MPG.
- ✔ No-Start Condition: The PCM controls the fuel pump and ignition coils. If it fails completely, the engine may crank but will not start.
- ✔ Erratic Transmission Shifting: The PCM works with the transmission control module to ensure smooth shifts. Hard or delayed shifting can be a sign of PCM failure.
- ✔ Failed Emissions Test: An inability to pass an emissions test is often directly related to a malfunctioning engine computer.
Plug-and-Play Solution with VIN Programming
Don’t risk installing a generic, unprogrammed module from a salvage yard. Our process ensures you receive a unit that is ready for installation right out of the box. Simply provide us with your vehicle’s 17-digit VIN during checkout, and our technicians will flash the module with the latest GM-certified software updates specific to your truck. This critical step ensures all systems communicate correctly and your vehicle operates as the manufacturer intended.
This PCM is a direct replacement for service number 12586242 and is also compatible with a wide range of other numbers, including 19299226, 89017738, YFKD, YFKF, YFKH, YFKJ, YFKX, YFXL, YFXM, YFXN, YFXP, and YHTN. It fits a large variety of 2004 GM trucks and SUVs. Please verify your part number and check the detailed fitment list to ensure compatibility.
Frequently Asked Questions
Do I need to get this computer programmed by a dealer?
No. We program the computer for you using your vehicle’s VIN before we ship it. It will arrive ready to be installed, saving you a trip to the dealership and expensive programming fees.
What is the difference between an ECM, PCM, and ECU?
The terms are often used interchangeably. ECM typically stands for Engine Control Module, while PCM (Powertrain Control Module) usually controls both the engine and the transmission. ECU (Electronic Control Unit) is a more generic term. For most 2004 GM trucks, PCM is the correct term as it manages the entire powertrain.
Where is the PCM located on my 2004 Sierra 1500?
On most GMT800 platform trucks like the Sierra, Silverado, Tahoe, and Yukon, the PCM is located in the engine bay on the driver’s side, typically under or next to the battery tray.
Will I need to perform a security relearn procedure after installation?
In some cases, a security relearn (often called a Passlock relearn) may be required. This is a simple procedure that can typically be done without special tools and involves cycling the ignition key. Instructions are readily available online for this process.
How do I find my original part number?
The part number or service number is printed on a sticker on the case of your original computer. You will need to locate and remove the computer to read this sticker. Matching this number is the best way to ensure you are ordering the correct part.