P068BECM/PCM Power Relay De-Energized Performance Too Late
- Generic OBD-II code · Powertrain
- How the car detects it
- The engine module switches its main relay coil to ground (control circuit), reads the switched voltage back on a sense line and keeps the relay on briefly after ignition off to save learned values. P068B is the counterpart of P068A: after ignition off and the module's switch-off command the relay voltage remains – the relay drops out late or not at all. GM Europe's 2.0 diesel runs this check from ignition off until the module shuts down and names a control line shorted to ground (coil stays energised), an output line shorted to voltage or a sticking contact as causes, without lighting the MIL. Modules and loads then stay powered and the battery drains. GM reports the same electrical faults as P0686/P0690 instead. A Ford diesel table lists 'P068B' for a memory error, which is evidently a typo for P06B8.
- What you may notice
- Relay or module stays active after ignition off (fan or pump keeps running)
- Battery drains
- Possibly check engine light (depending on the maker)
- Likely causes
- LikelyRelay contact sticking or welded
- PossibleRelay control wire shorted to ground (coil stays energised)
- PossibleRelay output or load line shorted to voltage
- RareModule driver or software
- Repair
- Easy · Often possible to do yourself.Typical cost: €10 – €250
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.