P1AA1

DTC P1A9C, P1A9D, P1AA0, or P1AA1

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 P1A9C
- Starter/Generator Inverter Phase U Temperature Sensor Circuit Low Voltage

DTC P1A9D
- Starter/Generator Inverter Phase U Temperature Sensor Circuit High Voltage

DTC P1AA0
- Starter/Generator Inverter Phase V Temperature Sensor Circuit Low Voltage

DTC P1AA1
- Starter/Generator Inverter Phase V Temperature Sensor Circuit High Voltage

Circuit/System Description

The power inverter module (PIM) temperature 1 and 2 sensors are used for overheat protection. The thermistors are located on the control board, near the phase U or V power MOSFET. The starter/generator control module (SGCM) monitors the inverter temperature sensor for the following:

* To detect if the inverter phase U or V temperature sensor is shorted low.
* To detect if the inverter phase U or V temperature sensor is shorted high.

If one of the above conditions is detected, the SGCM will set the appropriate DTC.

Conditions for Running the DTC

P1A9C, P1A9D, P1AA0, P1AA1

The engine is running.

Conditions for Setting the DTC

P1A9C, P1AA0

Sensor output voltage is less than 0.2 volt for 1 second.

P1A9D, P1AA1

Sensor output voltage is greater than 4.6 volts for 1 second.

Action Taken When the DTC Sets

P1A9C, P1A9D, P1AA0, P1AA1

50 percent maximum torque limit.

Conditions for Clearing the DTC

P1A9C, P1A9D, P1AA0, P1AA1

Normal range for 10 seconds.

Diagnostic Aids

P1A9C, P1AA0

Possible temperature sensor short to ground.

P1A9D, P1AA1

Possible temperature sensor short to voltage or open.

Circuit/System Verification

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.

P1A9C, P1A9D, P1AA0, P1AA1

If DTC is current, replace the SGCM.

Repair Instructions

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