Rule out the circuit around it
Power, ground, connectors, harness condition, the controlled load, mechanical faults, and command conditions can all produce similar symptoms.
Technical Repair Notes
Known Issues & Common Failures
Practical notes on recurring electronic faults, what the symptoms can mean, and what should be checked before a board is blamed.
Automotive Modules
ECM injector and ignition-coil output faults
A controller can still communicate and run most of the engine while one output stage fails to switch an injector or ignition coil correctly.
Technical noteBefore condemning a module Canada-wide review
ECM / ECU Injector & Ignition Coil Driver Failures
Diagnostic clues, external checks, output-driver basics, information for garages, a Subaru IC608 bench example, and the repair-review process.
Read the technical noteFor owners and repair shops
The Board Repair Guy is in Carleton Place, Ontario. Eligible modules can be reviewed for local service or Canada-wide mail-in repair.
Related Service Paths
Start with the service that matches the job
For a suspected module fault, see Automotive Electronics Repair. If the work involves damaged traces, pads or components on a circuit board, see Circuit Board & PCB Repair. Replacement-module data transfer is handled separately under ECU / ECM / BCM Module Cloning.