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 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. |
- 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.