P0612 Fuel Injector Control Module Relay Control Circuit

P0612 indicates a fuel injector control module relay control circuit problem. The controller cannot command or monitor the relay path that powers the injector control module correctly.

Code details

Generic OBD-II · P0

System: Computer
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not condemn the injector control module until its relay control circuit and loaded power feed are verified.

Symptoms of P0612

Check-engine light, sometimes with several unrelated codes at once.
Warning lights, a no-start, or intermittent electrical faults.
Communication or module-reset problems on a scan tool.

Common causes of P0612

Low battery voltage, poor grounds, corroded connectors, or blown fuses.
Wiring or network (CAN bus) faults between modules.
A module software/programming issue, or rarely a failed controller.

Useful checks before replacing parts

Check relay command, relay output voltage, fuse feed, current draw, injector control module power, freeze-frame data, and related low-voltage or injector codes.
Inspect relay contacts, fuse links, control wiring, ground path, connector heat damage, module power pins, and harness routing near high-current circuits.
Command the relay where supported and confirm voltage reaches the injector control module under load.

Related OBD-II codes

These nearby computer entries can help compare wording and pin down the fault area.