Diagnostic Instructions
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 engine water pump |
| • | Inoperative SGCM water pump |
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
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Verify the SGCM coolant pump operates.
- 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. |
- Inspect all 12-volt battery connections for a short to ground as follows:
- If all connections are normal, replace the SGCM.
Circuit/System Testing
SGCM Coolant Pump Malfunction
- Ignition OFF, disconnect the harness connector at the SGCM coolant pump.
- 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. |
- Ignition OFF, connect a test lamp between the B+ circuit terminal A and the control circuit terminal B.
- 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. |
- If all circuits test normal, test or replace the SGCM coolant pump
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
