B1492
DTC B1492
CIRCUIT DESCRIPTION
The generator battery control module monitors the generator through the generator field duty cycle signal circuit. The signal is a 5-volt pulse width modulation (PWM) signal of 128 Hz with a duty cycle of 0-100 percent. Normal duty cycle is between 5-95 percent. If the generator field duty cycle signal circuit is in the 0-5 percent range or pulled low to ground, then DTC B1492 will set.
DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC B1492 Generator F-Terminal Circuit Low
CONDITIONS FOR RUNNING THE DTC
- The engine speed is less that 1,000 RPM.
- DTC B1487 or B1488 is not set as a current DTC.
CONDITIONS FOR SETTING THE DTC
The generator field duty cycle signal circuit is less than or equal to 5 percent duty cycle for more than 120 seconds.
ACTION TAKEN WHEN THE DTC SETS
The generator battery control module will request the driver information center (DIC) message of Charging System Fault and commands ON the Battery indicator.
CONDITIONS FOR CLEARING THE DTC
- The generator field duty cycle signal circuit input is greater than 5 percent duty cycle.
- Clear the DTC with a scan tool.
DIAGNOSTIC AIDS
Recommended Action:
- Correct F-Term short low condition.
- Clear the codes.
- Cycle the ignition.
IMPORTANT: You must cycle the ignition after clearing the DTC to turn OFF the DIC message of Service Charging System.
If a fault condition persists, replace the module.
TEST
