P0A37

DTC P0A37

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P0A37
- Starter/Generator Temperature Sensor Performance

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 degrees Celsius (80 degrees Fahrenheit) and engine OFF timer greater than 480 minutes of start up.

Action Taken When the DTC Sets

50 percent maximum torque limit.

Conditions for Clearing the DTC

Normal range for 10 seconds.

Diagnostic Aids

Possible Internal failure at temperature sensor.

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.

1. Disconnect harness connector C2 from the SGCM.
2. Using the appropriate test adapters, test for less than 1 ohm resistance between terminals 2 and 14.

• If within the specified range, replace the SGCM.

3. Disconnect the 7 pin connector at the MGU.
4. Test for less than 1 ohm between SGCM connector harness terminal 2 and the MGU connector harness terminal G.

• If less than the specified range, repair the open circuit.

5. Test for less than 1 ohm between SGCM connector harness terminal 14 and the MGU connector harness terminal F.

• If less than the specified range, repair the open circuit.

6. If both circuits test normal, replace the MGU.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

Control Module References for SGCM replacement, setup, and programming.

Generator with Starter Replacement for MGU replacement.