Restore Your Truck’s Core Performance
When the brain of your engine starts to fail, your entire vehicle suffers. If your 2004 GM truck or SUV is experiencing perplexing issues like stalling, erratic shifting, a persistent check engine light, or a complete no-start condition, a faulty Engine Control Module (ECM) is often the culprit. This direct replacement ECM, compatible with service number 12586242, is the definitive solution to get your dependable vehicle back on the road. We take the guesswork out of the repair by pre-programming the module to your vehicle’s specific VIN, ensuring a seamless installation process without a costly trip to the dealership.
Common Symptoms & Your Solution
A failing ECM can manifest in numerous ways, often mimicking other component failures. If you’re dealing with any of the following, this module is your answer:
- No-Start or Hard Starting: The engine cranks but refuses to fire up, or takes an extended time to start.
- Unexplained Stalling: Your vehicle shuts off unexpectedly while driving or idling.
- Poor Performance & Fuel Economy: A noticeable drop in power, acceleration, and miles per gallon.
- Check Engine Light with Communication Codes: Diagnostic Trouble Codes (DTCs) like P0601, P0602, or P0606 indicate an internal module failure.
- Erratic Transmission Shifting: Harsh or delayed gear changes controlled by the ECM.
By installing our VIN-programmed 2004 Sierra 3500 ECM 12586242, you are not just replacing a part; you are restoring the central command center of your vehicle’s powertrain for reliable, consistent operation.
Features & Benefits
- โ Plug & Play Installation: Arrives programmed to your VIN. No additional programming or dealer visits required.
- โ Latest GM Software Updates: We flash each module with the newest software from GM to optimize engine efficiency, fuel economy, and emissions performance.
- โ Guaranteed Compatibility: A direct fit for vehicles requiring service numbers 12586242, 19299226, 89017738, and others listed in the fitment guide.
- โ Cost-Effective Solution: Get the precise part you need without the high markup and programming fees of a dealership service center.
- โ Restored Dependability: Solve frustrating electrical gremlins and trust your truck or SUV to perform when you need it most.
- โ Purchase with Confidence: This unit is backed by our one-year replacement warranty.
Expert Insight: The Critical Role of VIN Programming
As a technician with over two decades of experience, I’ve seen countless issues arise from improperly matched control modules. Simply grabbing a used computer from a salvage yard is a recipe for disaster. Your vehicle’s VIN contains critical information about its specific optionsโfrom the transmission type and gear ratio to its emissions system and security settings. Our VIN-specific programming ensures that this new ECM communicates flawlessly with all other modules in your vehicle. This prevents security system lockouts (anti-theft), incorrect transmission shift points, and a host of other frustrating problems that can leave you stranded. We ensure the job is done right the first time.
Frequently Asked Questions
What information do you need to program the ECM?
After you complete your purchase, we will require your vehicle’s 17-digit Vehicle Identification Number (VIN). This allows us to flash the module with the exact software and calibrations for your specific truck or SUV.
Is this part truly plug-and-play?
Yes. Because we program the unit to your VIN before shipping, it is ready for installation upon arrival. In most cases, you will simply need to disconnect the battery, swap the modules, and reconnect the battery. Some vehicles may require a security relearn procedure, which is a simple process that can be done without special tools.
How can I confirm this is the right part for my vehicle?
The best way is to match the service number on your current ECM to one of the numbers listed in our description, such as 12586242. You can also use the comprehensive fitment list provided on this page to check your make, model, and engine size.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the old ECM (indicated by codes like P0601 or P0606), then this replacement module will solve the problem. However, if the light is on due to other issues (like a bad sensor), those problems will still need to be addressed separately.
Where is the ECM located on my vehicle?
On most 2004 GM full-size trucks and SUVs (like the Sierra, Silverado, and Tahoe), the ECM is located in the engine bay on the driver’s side, under or near the battery. On mid-size SUVs (like the Trailblazer and Envoy), it is typically found next to the air filter box.