P0A89

DTC P0A88 or P0A89

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) 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 (Connector Views)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information


Circuit/System Verification

Caution: To help avoid personal injury, additional precautions must be taken prior to working on the generator control module or the generator starter. After removing the 36V battery cables from the generator battery, remove both engine wiring harness connectors from the generator control module. Wait at least 5 minutes and then remove the generator control module cover. Verify voltage levels at all 36V, 12V, and 3-phase connections, are less than 3 volts using a DMM before proceeding.


If DTC is current, replace the SGCM.


Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.


Control Module References (Programming and Relearning) for SGCM replacement, setup, and programming