Diagnostic Instructions

DTC Descriptors

DTC P0A9C: Hybrid Battery 1 Temperature Sensor Performance

DTC P0AC6: Hybrid Battery 2 Temperature Sensor Performance

DTC P0ACB: Hybrid Battery 3 Temperature Sensor Performance

DTC P0AE9: Hybrid Battery 4 Temperature Sensor Performance

DTC P1A19: Hybrid Battery 5 Temperature Sensor Performance

DTC P1A1C: Hybrid Battery 6 Temperature Sensor Performance

Circuit/System Description

The battery energy control module (BECM) monitors the hybrid battery pack temperature sensors to detect the failure of any sensor during a rationality check.

Conditions for Running the DTC

Ignition ON

Conditions for Setting the DTC

Module temperature 1, 2, 3, 4, 5, or 6 - module temperature average is greater than battery rationality threshold. Where battery rationality threshold equals as follows:

In: Tpack	Out: Temperature Threshold
-40	8
-30	8
-20	8
-10	8
0	8
10	8
20	8
30	8
40	8
50	8
60	8

Action Taken When the DTC Sets

Does not affect hybrid system operation.

Conditions for Clearing the DTC

Battery module temperature sensors are less than 8°C (46.4°F) different from the average of all temperatures.

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 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.

Caution: 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.

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

P0A9C

Battery 1 temperature sensor terminals 3 and 4

P0AC6

Battery 2 temperature sensor terminals 5 and 6

P0ACB

Battery 3 temperature sensor terminals 7 and 8

P0AE9

Battery 4 temperature sensor terminals 13 and 14

P1A19

Battery 5 temperature sensor terminals 15 and 16

P1A1C

Battery 6 temperature sensor terminals 17 and 18

Important:  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:

Important: 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.