P1A9B

DTC P1A9B

Diagnostic Instructions

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



DTC Descriptor
DTC P1A9B
- Starter/Generator Inverter Phase U Temperature Sensor Performance




Circuit/System Description

The power inverter module (PIM) temperature 1 sensor is used for overheat protection. The thermistor is located on the control board, near the phase W power MOSFET. The starter/generator control module (SGCM) monitors the inverter temperature sensor to detect the failure of the inverter temperature sensor circuit using rationality of other temperature sensors to determine if it is out of range.


Conditions for Running the DTC

The engine is running.


Conditions for Setting the DTC

Inverter temperature sensor is greater than 55°C (131°F) for 2 seconds.


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


Reference Information
Schematic Reference

Hybrid Controls Schematics ()
Connector End View Reference

Component Connector End Views (Connector Views)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning)for Scan Tool Information


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.


If DTC is current, replace the SGCM.


Repair Instructions

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


Generator Control Module Replacement ()for SGCM replacement, setup, and programming