Diagnostic Instructions
DTC Descriptor
DTC P1A7B: Starter/Generator Control Module Temperature Sensor Performance
Circuit/System Description
The starter/generator control module (SGCM) monitors the temperature sensors to determine if the sensor is reading correctly, by comparing it to average of 3 other sensors after 480 minute soak.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
The average (PIMTEMP 1, PIMTEMP 2, APMTEMP) - BOARDTEMP is greater than 30°C (86°F)
Action Taken When the DTC Sets
• | 50 percent maximum torque limit |
• | APM 50 percent maximum current output |
Conditions for Clearing the DTC
Return to normal range for 10 seconds.
Diagnostic Aids
• | Possible internal failure of the temperature sensor |
• | Restricted radiator air flow |
• | Restricted engine coolant flow |
• | Faulty engine water pump |
• | Inoperative SGCM coolant pump |
Reference Information
Schematic Reference
Hybrid Cooling Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Starter Generator Control Module Cooling System 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. |
- Ignition ON, observe the scan tool SGCM temperature sensor parameters.
⇒ | If only the SGCM board temperature sensor reads high, 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.