Programmed 2004 S10 Sonoma PCM 12586243

Restore Peak Performance to Your 2004 S10 or Sonoma

Is your trusty 2004 Chevy S10, GMC S15, or Sonoma suddenly giving you headaches? If you’re dealing with a persistent Check Engine Light, rough idling, stalling, or a frustrating no-start condition, the problem often points directly to a failing Powertrain Control Module (PCM). As the central computer for your truck’s engine, a faulty PCM can disrupt everything from fuel delivery and ignition timing to transmission shifting. This isn’t just an annoyance; it affects your truck’s reliability, fuel economy, and ability to pass emissions tests.

This replacement Electronic Control Module, part number 12586243, is the definitive solution. We take the guesswork and dealership hassle out of the repair. Before we ship it, we program the module with the latest GM-certified software updates, tailored specifically to your truck using its unique Vehicle Identification Number (VIN). This means you receive a part that is truly plug-and-play, ready to restore your engine’s proper function right out of the box. Getting your 2004 S10 Sonoma PCM replaced has never been more straightforward.

From the Diagnostic Bay: The Case of the Intermittent S10

A customer brought in his ’04 S10 with a 4.3L V6. The complaint was maddening: sometimes it would start perfectly, other times it would just crank and crank. There were no consistent trouble codes, just a random U0100 (Lost Communication with ECM/PCM) that would pop up and disappear. We checked all the usual suspects—battery, grounds, ignition switch, fuel pump. Everything tested fine. On a hunch, I tapped the PCM housing with a screwdriver handle while the engine was running, and it immediately stumbled. That confirmed our suspicion: an internal failure in the original module. Instead of sending him to a dealer for a costly replacement and programming session, we installed one of our pre-programmed modules. The truck fired up instantly, and the intermittent no-start was gone for good. The customer saved hundreds and got his reliable work truck back the same day.

Is Your Truck Showing These PCM Failure Signs?

✔ Check Engine Light is illuminated with codes like P0601, P0602, P0605, or P0606 (Internal Control Module errors).
✔ The engine cranks but refuses to start.
✔ Unexplained stalling or rough, erratic idling.
✔ Noticeable decrease in fuel efficiency.
✔ Harsh or incorrect automatic transmission shifting.
✔ Failure to pass state emissions inspections.
✔ Communication errors with diagnostic scan tools (e.g., U0100).

A Straightforward Guide to Installation

Replacing the 2004 S10 Sonoma PCM is a job most DIYers can handle with basic tools. The module is located in the right-hand front of the engine compartment.

Safety First: Always disconnect the negative terminal from your truck’s battery before starting any electrical work.
Locate the PCM: Open the hood and find the module on the passenger side of the engine bay, typically near the firewall or inner fender.
Disconnect the Connectors: Carefully unlatch and remove the electrical wiring harnesses from the old PCM. The levers can be stiff, so apply steady, even pressure. Inspect the connectors for any corrosion or damage.
Remove the Old Module: Unbolt the PCM from its mounting bracket. It’s usually held in by two or three bolts.
Install the New Module: Mount your new, pre-programmed PCM onto the bracket and secure the bolts.
Reconnect Everything: Firmly plug the wiring harnesses back into the new module until they click and lock into place. Reconnect the negative battery terminal.
Final Step: While the module is programmed to your VIN, some vehicles may require a security or crankshaft position sensor (CASE) relearn procedure. This can often be done with a capable bidirectional scan tool or may resolve itself after a few drive cycles.

Verified Vehicle Compatibility

This module is a direct replacement for part numbers 12586243 and 89017739. It is guaranteed to fit the following 2004 models. Please verify your part number or contact us with your VIN to ensure compatibility.

S10/S15/SONOMA 04: Electronic Control Module; (RH front engine compartment)
BLAZER S10/JIMMY S15 04: Electronic Control Module; (RH front engine compartment)
ASTRO 04: Electronic Control Module; (LH front by battery)
SAFARI (GMC) 04: Electronic Control Module; (LH front by battery)
AVALANCHE 2500 04: Electronic Control Module; (LH front under battery)
CORVETTE 04: Electronic Control Module; (RH engine compartment), ID 12586243
CTS 04-05: Electronic Control Module; (RH engine compartment), V-Series, ID 12586243
EXPRESS/SAVANA 1500/2500/3500 VAN 04: Electronic Control Module; (LH rear engine compartment)
GTO 04: Electronic Control Module; main (LH engine)
SILVERADO/SIERRA 1500 PICKUP 04: Electronic Control Module; (LH front under battery), w/4.3L
SILVERADO/SIERRA 2500/3500 PICKUP 04: Electronic Control Module; (LH front under battery), gasoline, 8.1L
SUBURBAN 2500 04: Electronic Control Module; (LH front under battery), 8.1L
YUKON XL 2500 04: Electronic Control Module; (LH front under battery), 8.1L
ENVOY XL/XUV, TRAILBLAZER EXT, RAINIER, SSR 04: Electronic Control Module; 5.3L (various IDs, please verify)

Don’t let a failing computer keep your truck off the road. Order this pre-programmed 2004 S10 Sonoma PCM today and restore the smooth, reliable operation you depend on.