P0A37
DTC P0A37
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC P0A37
- Starter/Generator Temperature Sensor Performance
Diagnostic Fault Information
Circuit/System Description
The starter/generator control module (SGCM) monitors the performance of the motor generator temperature sensor to detect if it is within range of the other temperature sensors, by comparing it to other temperature sensors it controls.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
Power inverter module (PIM) TEMP 1, PIM TEMP 2, auxiliary power module (APM) TEMP, Board TEMP, motor/generator unit (MGU) TEMP greater than 30°C (86°F) and engine OFF timer greater than 480 minutes of start up.
Action Taken When the DTC Sets
Hybrid system torque will be limited to 50 percent
Conditions for Clearing the DTC
The MGU temperature sensor returns normal range for 10 seconds
Reference Information
Schematic Reference
Hybrid Controls Schematics (Hybrid Controls Schematics)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Starter/Generator Description and Operation (Description and Operation)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
Ignition ON, observe the scan tool Starter Generator Temperature parameter. The reading should be less than 30°C (86°F) and the Engine Time Off parameter is greater than 480 minutes.
Circuit/System Testing
1. Verify DTCs P0A38 or P0A39 are not set.
• If P0A38 or P0A39 are set diagnose those first.
2. Ignition OFF, disconnect the X1 harness connector at the Starter Generator. Refer to Generator Control Module Replacement (Generator Control Module Replacement).
3. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 10 ohm between the low reference circuit terminal F and ground.
• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the SGCM.
4. Ignition ON, verify the scan tool Starter Generator Temperature parameter is less than -39°C (-38.2°F).
• If greater than the specified range, test the signal circuit terminal G for a short to ground. If the circuit tests normal, replace the SGCM.
5. Install a 3 A fused jumper wire between the signal circuit terminal G and the low reference circuit terminal F. Verify the scan tool Starter Generator Temperature parameter is greater than 100°C (212°F).
• If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the SGCM.
6. If all circuits test normal, test or replace the Starter Generator.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Generator with Starter Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for SGCM replacement, programming and setup