Values In Fault Memory Not Plausible Drive Cycle A

DTC P0603
Values in fault memory not plausible Drive cycle A:Signal implausible.

Possible causes by suggested order of priority:
- Battery connections/condition.
- Severe environmental conditions.
- Faulty Motronic ECM.

Battery connections/condition.
- Check voltage 10.0 to 14.0 volts

Severe environmental conditions.
- ECM has been operated at extremely high ambient temperature.
- The ECM may temporarily fail if it's temperature rises to about 130°C.
- This would not normally be expected to happen even in ambient temperatures >40°C.

Faulty Motronic ECM.
- Permanent supply fault flag is not set.
- Freeze frame data for battery voltage logged when fault occurred was >6V.
- Clear all faults and monitor for re-occurance.
- If fault repeatedly reoccurs - faulty Motronic ECM.