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 P1A9E: Starter/Generator Inverter Phase U OvertemperatureDTC P1AA2: Starter/Generator Inverter Phase V Overtemperature
Circuit/System Description
The power inverter module (PIM) temperature 1/2 sensor is used for overheat protection. The thermistor is located on the control board, near the phase U/V power MOSFET. The SGCM monitors the inverter temperature sensor for the following:
| • | To detect if the inverter phase U/V temperature sensor is shorted low. |
| • | To detect if the inverter phase U/V temperature sensor is shorted high. |
If one of the above conditions is detected, the SGCM will set the appropriate DTC.
Conditions for Running the DTC
P1A9E, P1AA2
The engine is running.
Conditions for Setting the DTC
P1A9E, P1AA2
Temperature is greater than 175°C (347°F) for 20 ms.
Action Taken When the DTC Sets
P1A9E, P1AA2
Stop PWM (MGU shutdown)
Conditions for Clearing the DTC
P1A9E, P1AA2
Temperature is less than 150°C (302°F) for 2.5 seconds.
Diagnostic Aids
P1A9E, P1AA2
Possible 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
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 Testing
- Inspect the 3 phase cable connections at the SGCM. Refer to Generator Control Module Replacement
- Verify that the 3 phase cables are torqued to within specifications. Refer to Fastener Tightening Specifications
- With a scan tool, clear the DTC.
- Ignition OFF, wait 30 seconds.
- Ignition ON, operate the vehicle within the Conditions for Running the DTC.
| ⇒ | 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
