P0612Fuel Injector Control Module Relay Control
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- Some diesels have a separate injector driver module that is powered through a relay switched by the engine module – GM's 6.6 L Duramax LB7/LLY with its injector driver unit, Ford's 6.0 L Power Stroke with its injector control module. P0612 means the commanded relay state and the voltage measured back at the output do not match. GM checks this with ignition on and the CAN link initialised, outside the shutdown phase, and sets the code after 30 of 50 checks at 125 ms; the lamp follows after two trips. If the relay fails, the injector module gets no power – the engine does not start or stalls; if it does not drop out, the module stays powered and drains the battery. Newer diesels have the injector drivers inside the engine module and use P062D/P062E instead. A fault reported by the injector module itself is P0611.
- What you may notice
- Engine does not start or stalls while driving
- Check engine light (GM after two trips)
- Battery drain if the relay does not drop out
- Often together with P0611 or injector codes
- Likely causes
- LikelyInjector module relay faulty (coil open, contacts welded)
- PossibleRelay control or feedback wire open or corroded, fuse
- PossibleLow battery voltage or ground problems
- RareDriver in the engine module faulty
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €20 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.