P0AF7

DTC P0AF7

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 Descriptor
DTC P0AF7
- 14 Volt Power Module Overtemperature

Circuit/System Description

The auxiliary power module (APM) temperature sensor is used for overheat protection. The thermistor is located on the control board, near the phase APM power MOSFET. The starter/generator control module (SGCM) monitors the board temperature sensor for an APM overtemperature condition.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

APM temperature sensor is greater than 80°C (175°F) for 2 seconds.

Action Taken When the DTC Sets

APM PWM off

Conditions for Clearing the DTC

FET temperature for APM is less than 150°C (302°F) for 2.5 seconds.

Diagnostic Aids

Possible engine or SGCM cooling system failure due to the following:

* Restricted radiator air flow
* Restricted engine coolant flow
* Faulty thermostat
* Faulty engine water pump
* Inoperative SGCM water pump

Reference Information
Schematic Reference

Hybrid Controls Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Starter/Generator Description and Operation (Description and Operation)
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

1. Verify the SGCM coolant pump operates.
2. Ignition ON, command the scan tool SGCM coolant pump output control ON and OFF.

• If the SGCM coolant pump does not operate refer to SGCM Coolant Pump Malfunction.

3. Inspect all 12-volt battery connections for a short to ground as follows:

* At battery
* At SGCM
* At fuse block

4. If all connections are normal, replace the SGCM.

Circuit/System Testing
SGCM Coolant Pump Malfunction

1. Ignition OFF, disconnect the harness connector at the SGCM coolant pump.
2. Ignition ON, test for B+ between the B+ circuit terminal A and ground.

• If less than the specified value, test the B+ circuit for a short to ground or an open/high resistance.

3. Ignition OFF, connect a test lamp between the B+ circuit terminal A and the control circuit terminal B.
4. Ignition ON, command the SGCM Coolant Pump Relay ON and OFF with a scan tool. The test lamp should turn On and OFF when commanded.

• If the test lamp does not turn ON and OFF when commanded, test the control circuit for an open/high resistance. If the circuit tests normal, replace the SGCM.

5. If all circuits test normal, test or replace the SGCM coolant pump

Repair Instructions

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

* Generator Control Module Coolant Pump Replacement (Generator Control Module Coolant Pump Replacement)
* Control Module References (Programming and Relearning) for SGCM replacement, setup, and programming