GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2009 🢒 VUE - AWD 🢒 DTC 🢒 DTC P0A88 or P0A89

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 Current

DTC 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

Hybrid Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Starter/Generator Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification
  1. With a scan tool, clear the DTC.
  2. Ignition OFF, wait 30 seconds.
  3. Ignition ON, operate the vehicle within the Conditions for Running the DTC and verify the DTC does not reset.
    4. ⇒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