• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Generator L-Terminal Circuit | B1487 | -- | B1488 | -- |
The generator battery control module (GBCM) controls the generator through the generator turn on signal circuit, or L-terminal circuit. The signal is a 5-volt pulse width modulation (PWM) signal of 128 Hz, and the GBCM varies the duty cycle. Normal duty cycle is between 5-95 percent when the engine is running. If the generator turn on signal circuit is 95 percent or greater duty cycle or pulled high to voltage, then DTC B1488 will set.
• | The ignition is ON. |
• | The engine is OFF. |
The generator turn on signal circuit is greater than 95 percent for 5 seconds.
• | The charge indicator turns ON. |
• | The driver information center (DIC) displays the BATTERY NOT CHARGING message. |
The DTC will pass when the generator turn on signal circuit is less than 95 percent for 5 seconds.
Starting and Charging Schematics
Charging System Description and Operation
Control Module References for scan tool information
⇒ | If greater than the specified range, test the generator turn on signal circuit for a short to voltage. If the circuit tests normal, replace the GBCM. |
⇒ | If less than the specified range, test the generator turn on signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the GBCM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for GBCM replacement, setup, and programming. |