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.
This diagnostic procedure supports the following DTC:
DTC B1488 Generator L-Terminal Circuit High
• | 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. |
The generator field control circuit is 0 percent and shorted high to battery voltage, 5 volts, for greater than 5 seconds.
The generator battery control module will request the driver information center (DIC) message of Service Charging System and commands ON the Battery indicator.
• | The generator field control circuit voltage is 0 volts. |
• | Clear the DTC with a scan tool. |
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 |