Circuit Description
The generator battery control module (GBCM) controls the generator through the charge indicator control circuit, or L-terminal circuit. The signal is a 5 volt pulse width modulated (PWM) signal of 128 Hz. Normal duty cycle is between 5-95 percent when the engine is running.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B1487 Generator L-Terminal Circuit Low
Conditions for Running the DTC
| • | The engine is running |
| • | This diagnostic shall be run every 100 ms |
Conditions for Setting the DTC
The charge indicator control circuit is less than 5 percent duty cycle for 2 minutes.
Action Taken When the DTC Sets
| • | The charge indicator turns ON. |
| • | The driver information center (DIC) displays the BATTERY NOT CHARGING message. |
Conditions for Clearing the DTC
| • | The charge indicator control circuit input is 5-95 percent duty cycle, and greater than 0 V. |
| • | You must cycle the ignition after clearing the DTC to turn OFF the DIC message and charge indicator. |
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Starting and Charging Schematics Connector End View Reference: Engine Electrical Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
2 |
Is the reading greater than the specified value? | 2.5 volts | Go to Step 3 | Go to Step 4 |
3 | Inspect for poor connections at the harness connector of the generator. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs. Did you find and correct the condition? | -- | Go to Step 7 | Go to Step 5 |
4 | Test the charge indicator control circuit for a short to ground, an open or high resistance. Did you find and correct the condition? | -- | Go to Step 7 | Go to Step 6 |
5 | Replace the generator. Refer to Generator Replacement. Did you complete the replacement? | -- | Go to Step 7 | -- |
6 | Replace the generator battery control module. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 7 | -- |
7 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
