B412

Chart:

Schematic:

DESCRIPTION
Code B412 will set when the ignition is on, the engine RPM is greater than 800 and the Body Control Module (BCM) is seeing an ignition-1 fuel reference voltage of more than 16 volts. During the time the failure is present the cruise control will be disengaged. This code should be fixed before trusting any other code that has been set as high voltage could cause false setting of codes.

TEST DESCRIPTION
The numbers below refer to circled numbers on the diagnostic chart:
1. BCM data value BD50 displays battery voltage. The normal range is between 10 and 16 volts.
2. Check to see if the high voltage reading is due to the generator or BCM. With engine running, check voltage at the battery. if the voltage is above 16 volts the BCM is OK.
3. Check to see if generator is faulty under load condition. If the voltage is above 16 volts refer to alternator diagnosis.

NOTE ON INTERMITTENTS
If an intermittent Code B412 is being set, observe BCM data value BD50. This battery voltage reading is monitored off of the 10 Amp ISO IGN 1 fuse. fuel reference voltage, which is also used to set Code B411.