Diagnostic Instructions
DTC Descriptors
DTC P1A9E: Starter/Generator Inverter Phase U Overtemperature
DTC 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 MGU 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
PP1A9E, P1AA2
Possible 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
Hybrid Controls Connector End Views
Electrical Information Reference
Scan Tool Reference
Scan Tool Data List
Circuit/System Testing
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.
- 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
.
| ⇒ | If the 3 phase cables are within specifications, replace the SGCM. |
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
Control Module References
for SGCM replacement, setup, and programming
