Circuit Description
The generator battery control module controls the generator through the generator field control circuit, charge indicator control 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 control circuit is 0 percent duty cycle or pulled high to battery positive voltage, 5 volts, then DTC B1488 will set.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B1488 Generator L-Terminal Circuit High
Conditions for Running the DTC
| • | Vehicle in RUN mode and Engine Run Flag is False. |
| • | The engine RPM is less than or equal to 0 RPM. |
| • | This diagnostic shall be run every 100 ms. |
Conditions for Setting the DTC
The generator field control circuit is 0 percent and shorted high to battery voltage, 5 volts, for greater than 5 seconds.
Action Taken When the DTC Sets
The generator battery control module will request the driver information center (DIC) message of Service Charging System and commands ON the Battery indicator.
Conditions for Clearing the DTC
| • | The generator field control circuit voltage is 0 volts. |
| • | Clear the DTC with a scan tool. |
Diagnostic Aids
Important: You must cycle the ignition after clearing the DTC to turn OFF the DIC message of Service Charging System.
Recommended Action:
| • | Correct L-Term short high 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 and turn OFF the battery indicator.
If a fault condition persists, replace the module.
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 | With a DMM, test the charge indicator control circuit of the generator battery control module. Is the DMM reading equal to or above the specified value? | 5 V | Go to Step 4 | Go to Step 3 |
3 | Inspect for poor connections at the harness connector of the generator battery control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 6 | Go to Step 5 |
4 | Repair the short to battery positive voltage of the charge indicator control circuit. Did you find and correct the condition? | -- | Go to Step 6 | Go to Step 5 |
5 | Replace the generator battery control module. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 6 | -- |
6 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
