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.
VOLTAGE_12
^ Check voltage 10.0 to 14.0 volts.

Severe Environmental Conditions.
CHECK THE FOLLOWING:
^ ECM has been operated at extremely high ambient temperature.
INFORMATION
^ The ECM may temporarily fail if it's temperature rises to about 130° C (266° F).
^ This would not normally be expected to happen even in ambient temperatures > 40° C (266° F).

Faulty Motronic ECM.
CHECK THE FOLLOWING:
^ Permanent supply fault flag is not set.
^ Freeze frame data for battery voltage logged when fault occured was >6V.
^ Clear all faults and monitor for re-occurance.
POSSIBLE FAULTS
^ If fault repeatedly re-occurs - faulty Motronic ECM.