Important Information – Used ECMs

• Tested & Verified: Good, tested used electrical components.

• Programming Required: Must be flashed to your vehicle’s specific VIN by a dealer or qualified diesel shop before installation.

• Programming Not Included: Buyer is responsible for all programming.

• Return Policy: Electrical components that have been opened, installed, or plugged in are generally non-returnable unless covered under warranty.

12586243 Used GM/Chevrolet 5.3L Engine Control Module (ECM/PCM)

This used GM 12586243 Engine Control Module (ECM), also known as a Powertrain Control Module (PCM), is designed for compatible Chevrolet and GMC vehicles equipped with 5.3L V8 gasoline engines and select other GM engine configurations.

The 12586243 ECM belongs to the GM P59 controller family and manages essential engine operating functions, including fuel injection, ignition timing, sensor inputs, engine diagnostics, and other electronic powertrain controls.

A tested used OEM GM ECM offers a cost-effective replacement option for a failed or malfunctioning engine computer. It can help reduce repair expenses while maintaining the original electronic control architecture of compatible vehicles.

Programming is required before installation. The buyer must arrange for the ECM to be flashed with the correct VIN-specific calibration by a qualified automotive programming specialist, dealer, or repair facility. Additional vehicle security relearn procedures may be necessary.

Important Compatibility Note: GM part number 12586243 was used across multiple engine sizes and vehicle platforms. Matching the service number alone does not guarantee compatibility. Verify the original ECM part number, hardware configuration, vehicle VIN, engine size, and calibration requirements before ordering.

Part Specifications

OEM Part Number: 12586243
Stock Number: 10E-12586243-STK
Manufacturer: General Motors (GM)
Component Type: Engine Control Module / Powertrain Control Module (ECM/PCM)
Controller Family: GM P59
Condition: Used – Tested
Primary Listed Engine: GM/Chevrolet 5.3L V8
Additional Engine Applications: Select GM 4.3L, 4.8L, 5.7L, 6.0L, and 8.1L configurations, subject to compatibility verification
Fuel Type: Gasoline
Hardware Number: 125853659 – As Listed, Pending Verification
Programming Required: Yes – VIN-Specific
Programming Included: No
Typical Applications: Chevrolet and GMC Vans, Trucks, SUVs, and Select Commercial Vehicles

Common Applications

This GM 12586243 ECM may be compatible with select vehicles equipped with the appropriate P59 engine control system, including:

• Chevrolet Express 1500, 2500, and 3500 Vans – Select 2004 Applications

• GMC Savana 1500, 2500, and 3500 Vans – Select 2004 Applications

• Chevrolet TrailBlazer EXT – 2003–2004, Select 5.3L V8 Applications

• GMC Envoy XL / Envoy XUV – Select 2004 5.3L V8 Applications

• Chevrolet Silverado – Select 2004 Gasoline Engine Configurations

• GMC Sierra – Select 2004 Gasoline Engine Configurations

• Chevrolet Astro / GMC Safari – Select 2004 4.3L V6 Applications

• Chevrolet Suburban / GMC Yukon XL – Select 2004 8.1L Applications

• Chevrolet Kodiak / GMC TopKick – Select 2004 Gasoline Engine Applications

These represent documented vehicle families associated with this ECM or its aftermarket equivalents, not guaranteed fitments for every engine and trim.