B411

BCM Code B411 Or B412:

Battery Voltage Circuit:

DESCRIPTION:

The BCM monitors ignition 1 voltage on terminal "3C11" as a reference for fuel control. Codes B411 and B412 are set when the ignition is "ON" and the engine speed is above 800 rpm as follows.

B411-Ignition 1 less than 1O volts.

B412-Ignition 1 more than 16 volts.

During the time the failure is present, the cruise control will be disengaged. The cause of these codes should be corrected before diagnosing any other code that has been set because low or high voltage can cause false setting of codes. A current B411 or B412 can be observed in BCM data display (BD50 "BATT VOLTS") outside the range of 10 to 16 volts.

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 10.6 and 16 volts.

2. Check to see if the low voltage readings are due to circuitry or the battery. With the engine running, if voltage is below 10 volts the BCM and wiring are OK.

3. Check to see if the low voltage reading is due to the circuit or the BCM. If the voltage at the BCM is below 10.6 volts, then the BCM is OK.

4. Check to see if the high voltage reading is due to the generator or faulty BCM.

5. Check to see if changing voltage goes too high with higher engine speed or electrical load.

NOTE ON INTERMITTENTS:

If an intermittent code B411 or B412 is being set, observe BCM data value BD50. This battery voltage reading is monitored from the 15A ISO IGN-1 fuse, fuel reference voltage. If the code is being set due to a high current draw in a certain vehicle component this can be observed by reading the display for BD50. Operate the various components while watching for the reading to drop below 10 volts or go above 16 volts. Code B411 could be due to intermittent open in CKT 39 which may be observed by manipulating the wire to the BCM while watching BD50 for voltage to drop below 10.