The deviation of the temperature across the battery pack is checked using the 6 temperature sensors. If one of the battery temperature readings is significantly higher or lower than the average, this DTC will set.

The engine is running.

If any of the following conditions exist:

Where DeltaT Threshold (In: Tpack, Out: temp threshold) =

Hybrid system is disabled.

The difference between any temperature sensor and the average of all sensors is less than or equal to the threshold.

Schematic Reference

Hybrid Energy Storage Schematics

Connector End View Reference

Hybrid Energy Storage Connector End Views

Electrical Information Reference

Scan Tool Reference

Scan Tool Data List

Special Tools

J 35616 GM Approved Terminal Test Kit

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.

1. If DTC is history, refer to Testing for Intermittent Conditions and Poor Connections .
2. Observe the scan tool Hybrid Battery 1 Temperature, Hybrid Battery 2 Temperature, Hybrid Battery 3 Temperature, Hybrid Battery 4 Temperature, Hybrid Battery 5 Temperature and Hybrid Battery 6 Temperature parameters in the BECM data list. The temperature sensors should be within 4 degrees Celsius or 7.2 degrees Fahrenheit of each other.

⇒	If any of the temperature sensor readings are not within the specified value, refer to Circuit/System Testing.

⇒	If all sensors are within the specified value after the three hour soak, replace the battery pack.

Important: In order to avoid damaging BECM C1 and C2 connector terminals, the proper test probes should be used. The proper test probes are as follows:

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

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 C1 from the BECM. Refer to Hybrid Battery Service Disconnect/Connect
2. Test for 10.5-11.5 kohms of resistance between the applicable temperature sensor circuit terminals.

⇒	If not within the specified range, disconnect the applicable temperature sensor from the wiring harness and test the wiring harness for a short to ground, open/high resistance and the two circuits shorted to each other. If the harness circuits do not test normal replace the wiring harness.

⇒	If the harness circuits test normal, replace the applicable temperature sensor.

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.