Diagnostic Instructions

DTC Descriptors

DTC P0A9D: Hybrid Battery 1 Temperature Sensor Circuit Low Voltage

DTC P0A9E: Hybrid Battery 1 Temperature Sensor Circuit High Voltage

DTC P0AC7: Hybrid Battery 2 Temperature Sensor Circuit Low Voltage

DTC P0AC8: Hybrid Battery 2 Temperature Sensor Circuit High Voltage

DTC P0ACC: Hybrid Battery 3 Temperature Sensor Circuit Low Voltage

DTC P0ACD: Hybrid Battery 3 Temperature Sensor Circuit High Voltage

DTC P0AEA: Hybrid Battery 4 Temperature Sensor Circuit Low Voltage

DTC P0AEB: Hybrid Battery 4 Temperature Sensor Circuit High Voltage

DTC P1A1A: Hybrid Battery 5 Temperature Sensor Circuit Low Voltage

DTC P1A1B: Hybrid Battery 5 Temperature Sensor Circuit High Voltage

DTC P1A1D: Hybrid Battery 6 Temperature Sensor Circuit Low Voltage

DTC P1A1E: Hybrid Battery 6 Temperature Sensor Circuit High Voltage

Circuit/System Description

Each battery module has a separate temperature sensor, or thermistor. These sensors are serviced as a pair (2 sensors for each battery module). The battery module must be removed from the vehicle in order to access the thermistors. These sensors receive power and provide a battery temperature feedback signal to the battery energy control module (BECM), through the generator battery temperature sensor wiring harness.

The battery temperature sensor is a 2-wire 10k ohm thermistor. The BECM supplies 5 volts and a low reference circuit to determine battery temperature.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

P0A9D, P0AC7, P0ACC, P0AEA, P1A1A, P1A1D

Temperature sensor less than 0.5 volt.

P0A9E, P0AC8, P0ACD, P0AEB, P1A1B, P1A1E

Temperature sensor greater than 4.5 volts.

Action Taken When the DTC Sets

If more than 2 circuit faults are detected the hybrid system is disabled.

Conditions for Clearing the DTC

The affected battery temperature sensor returns to a normal operating range.

Reference Information

Schematic Reference

Hybrid Energy Storage Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Generator Battery Carrier Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 35616 GM Approved Terminal Test Kit

Circuit/System Verification

P0A9D, P0AC7, P0ACC, P0AEA, P1A1A, P1A1D

With a scan tool observe the battery temperature sensor parameter for the affected sensor. The parameter should display greater than 0.5 volt to pass.

P0A9E, P0AC8, P0ACD, P0AEB, P1A1B, P1A1E

With a scan tool observe the battery temperature sensor parameter for the affected sensor. The parameter should display less than 4.5 volts.

Circuit/System Testing

Warning: 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.

Warning: To help avoid personal injury, be careful when working in the vicinity of the generator battery disconnect control module. Internal components will still be live, 36V potential, even when the cover has been opened or removed.

Note: Use the following list to identify the appropriate terminals to test:

P0A9D-P0A9E

Battery 1A temperature sensor terminals 3 and 4

P0AC7-P0AC8

Battery 1B temperature sensor terminals 5 and 6

P0ACC-P0ACD

Battery 2A temperature sensor terminals 7 and 8

P0AEA-P0AEB

Battery 2B temperature sensor terminals 13 and 14

P0A1A-P0A1B

Battery 3A temperature sensor terminals 15 and 16

P0A1D-P0A1E

Battery 3B temperature sensor terminals 17 and 18

Note: In order to avoid damaging BECM X1 and X2 connector terminals, the proper test probes should be used. The proper test probes are as follows:

Note: The following test must be performed when the battery pack has equalized at room temperature. An increase or decrease in temperature will cause resistance to change and may result in invalid test results.

1. Ignition OFF, disconnect harness connector X1 from the BECM. Refer to Hybrid Battery Service Disconnect/Connect.
2. Test for 10.5-11.5k ohms between the applicable temperature sensor circuit terminals.

⇒	If not within the specified range, test or replace the applicable temperature sensor.

3. If all circuits test normal, replace the BECM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.