Diagnostic Instructions
| • | 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. |
DTC Descriptors
DTC P0A88: 14-Volt Power Module Current Sensor Circuit Low CurrentDTC P0A89: 14-Volt Power Module Current Sensor Circuit High Current
Circuit/System Description
The auxiliary power module (APM) current sensor is used for over current limitation (less than 150A). The current sensor is soldered on the control board, near the APM 12-volt bus bar. The starter/generator control module (SGCM) monitors the current sensor for the following:
| • | To detect the failure of the APM current sensor circuit (high) |
| • | To detect the failure of the APM current sensor circuit (low) |
If one of the above conditions is detected, the SGCM will set the appropriate DTC.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
P0A88
Sensor signal for APM is less than +0.5 volt (-376A) for 0.5 ms.
P0A89
Sensor signal for APM is greater than 4.5 volts (376A) for 0.5 ms.
Action Taken When the DTC Sets
APM PWM off
Conditions for Clearing the DTC
Clears 30 seconds after cycle wake up signal
Diagnostic Aids
P0A88
Possible current sensor short to ground or open
P0A89
Possible current sensor short to voltage
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Starter/Generator Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- With a scan tool, clear the DTC.
- Ignition OFF, wait 30 seconds.
- Ignition ON, operate the vehicle within the Conditions for Running the DTC and verify the DTC does not reset.
| ⇒ | If the DTC resets, replace the SGCM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for SGCM replacement, setup, and programming
