Get Your Truck Back on the Road, Fast.
As a technician with over two decades of experience, I’ve seen firsthand the frustration a failing Powertrain Control Module (PCM) can cause. Your 2004 Chevy Blazer S10 or GMC Jimmy S15 might be stalling, shifting erratically, or refusing to start altogether. These aren’t just annoyances; they’re problems that can leave you stranded. You’re looking for a reliable fix, not another headache. This is it. This is a direct-replacement Electronic Control Module (ECM), part number 89017739, that serves as the brain for your truck’s engine and transmission.
The biggest hurdle with PCM replacement has always been the programming. In the past, you’d have to buy the part, install it, and then have your vehicle towed to a dealership for expensive flashing. We eliminate that step. When you order from us, we flash the module with the latest GM-certified software updates, programmed specifically to your vehicle’s VIN. This means it arrives at your door ready for a straightforward installation, saving you significant time and money. This isn’t just a part; it’s a complete solution to restore your vehicle’s performance, fuel economy, and reliability.
From the Diagnostic Bay: The Case of the Heat-Soaked S10
I remember a 2004 S10 that came into my shop with a maddeningly intermittent stalling issue. It would run perfectly fine for 15-20 minutes, but as soon as the engine bay got hot, it would sputter and die. The owner had already replaced the fuel pump and ignition coil, chasing a ghost. After hooking up my scan tool and monitoring live data, I noticed the injector pulse width would suddenly go erratic right before the stall. Tapping on the original PCM housing would sometimes replicate the issue. This is a classic sign of internal solder joints failing under heat. We installed one of our pre-programmed modules, and the problem was gone for good. It’s a reminder that a faulty 2004 Blazer S10 PCM can often mimic other component failures.
Signs Your S10/Jimmy PCM is Failing
A failing computer can cause a wide range of symptoms. If you’re experiencing any of the following, a faulty PCM is a likely culprit:
- âś” Check Engine Light is on with internal processor codes (e.g., P0601, P0602, P0606)
- âś” Vehicle will not start or has a hard starting condition
- âś” Poor or erratic automatic transmission shifting
- âś” Intermittent stalling or engine stumbling
- âś” Noticeable drop in fuel economy
- âś” Failure to pass an emissions inspection
- âś” Communication errors with scan tools
A Straightforward Guide to Installation
Installing your pre-programmed 2004 Blazer S10 PCM is a job most DIYers can handle in their own driveway. Follow these general steps to get your truck running smoothly again.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the Module: On the 2004 Blazer S10 and Jimmy S15, the PCM is located in the engine compartment on the right-hand (passenger) side, often near the firewall or inner fender.
- Disconnect the Connectors: Carefully unclip the wiring harness connectors from the old module. These connectors have locking tabs; be gentle to avoid breaking them.
- Remove the Old PCM: Unbolt the old module from its mounting bracket. Keep the hardware, as you may need it for the new installation.
- Install the New PCM: Mount your new, pre-programmed module in place and securely tighten the bolts.
- Reconnect Everything: Plug the wiring harnesses firmly into the new module until they click. Reconnect the negative battery terminal.
- Perform Security Relearn (If Needed): In some cases, you may need to perform a simple security relearn procedure. This usually involves turning the key to the ‘ON’ position for 10-15 minutes. Consult your owner’s manual for the specific steps for your vehicle.
Verified Fitment for Your GM Vehicle
While this is the correct part for the 2004 Blazer S10 and Jimmy S15, this versatile 2004 Blazer S10 PCM is also a direct replacement for a wide range of other 2004-2005 GM vehicles. Please confirm your part number (89017739 or 12586243) and check the list below:
- ASTRO 04 (LH front by battery)
- AVALANCHE 2500 04 (LH front under battery)
- BLAZER S10/JIMMY S15 04 (RH front engine compartment)
- CORVETTE 04 (RH engine compartment, ID 12586243)
- CTS 04-05 V-Series (RH engine compartment, ID 12586243)
- ENVOY XL 04 5.3L
- ENVOY XUV 04 5.3L
- EXPRESS 1500/2500/3500 VAN 04 (LH rear engine compartment)
- GTO 04 (LH engine)
- RAINIER 04 5.3L
- S10/S15/SONOMA 04 (RH front engine compartment)
- SAFARI (GMC) 04 (LH front by battery)
- SAVANA 1500/2500/3500 VAN 04 (LH rear engine compartment)
- SIERRA 1500 PICKUP 04 4.3L (LH front under battery)
- SIERRA 2500 PICKUP 04 8.1L Gas (LH front under battery)
- SIERRA 3500 PICKUP 04 8.1L Gas (LH front under battery)
- SILVERADO 1500 PICKUP 04 4.3L (LH front under battery)
- SILVERADO 2500 PICKUP 04 8.1L Gas (LH front under battery)
- SILVERADO 3500 PICKUP 04 8.1L Gas (LH front under battery)
- SSR 04
- SUBURBAN 2500 04 8.1L (LH front under battery)
- TRAILBLAZER EXT 04 5.3L
- YUKON XL 2500 04 8.1L (LH front under battery)
Frequently Asked Questions
Do I need to program this module?
No. We handle all the programming for you before we ship the part. Simply provide us with your vehicle’s 17-digit VIN during checkout, and we will flash the module with the latest GM software specific to your truck.
What is a VIN and where do I find it?
The VIN (Vehicle Identification Number) is your car’s unique 17-digit serial number. You can find it on your vehicle’s registration, insurance card, or on a small plate on the driver’s side of the dashboard, visible through the windshield.
Where is the PCM located on my 2004 S10 Blazer?
On the 2004 Blazer S10 and GMC Jimmy S15, the PCM is typically found in the engine compartment on the passenger’s side (RH side), mounted near the firewall or inner fender.
Will this fix my Check Engine Light?
If the Check Engine Light is caused by an internal failure of the PCM (common codes include P0601-P0606), then yes, this part is the correct fix. However, if the light is on for another reason (like a bad oxygen sensor), you will still need to address that separate issue.
What is the security relearn procedure?
It’s a simple process that syncs the new PCM with your vehicle’s anti-theft system. For most GM vehicles of this era, it involves turning the key to the ‘ON’ position (without starting the engine) for about 10-15 minutes, then turning it off, and then starting the vehicle normally. This allows the components to recognize each other.