Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC P1A5A: Hybrid Battery Pack TemperatureCircuit/System Description
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.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
If any of the following conditions exist:
| • | Module Temperature 1 - Module Temperatures Average is greater than DeltaT Threshold, or |
| • | Module Temperature 2 - Module Temperatures Average is greater than DeltaT Threshold, or |
| • | Module Temperature 3 - Module Temperatures Average is greater than DeltaT Threshold, or |
| • | Module Temperature 4 - Module Temperatures Average is greater than DeltaT Threshold, or |
| • | Module Temperature 5 - Module Temperatures Average is greater than DeltaT Threshold, or |
| • | Module Temperature 6 - Module Temperatures Average is grater than DeltaT Threshold |
Where DeltaT Threshold (In: Tpack, Out: temp threshold) =
In: Tpack | Out: Temperature Threshold |
|---|---|
-40°C (-40°F) | 4°C (7.2°F) |
-30°C (-22°F) | 4°C (7.2°F) |
-20°C (-4°F) | 4°C (7.2°F) |
-10°C (14°F) | 4°C (7.2°F) |
0°C (32°F) | 4°C (7.2°F) |
10°C (50°F) | 4°C (7.2°F) |
20°C (68°F) | 4°C (7.2°F) |
30°C (86°F) | 4°C (7.2°F) |
40°C (104°F) | 4°C (7.2°F) |
50°C (22°F) | 4°C (7.2°F) |
50°C (40°F) | 4°C (7.2°F) |
Action Taken When the DTC Sets
Hybrid system is disabled.
Conditions for Clearing the DTC
The difference between any temperature sensor and the average of all sensors is less than or equal to the threshold.
Diagnostic Aids
| • | The battery temperature sensors should be less than 4°C (7.2°F) from the average of all temperature sensors after allowing the vehicle to stand undisturbed for a minimum of three hours. |
| • | Airflow obstructions around hybrid battery, fan and fan base may cause this DTC to set. |
Reference Information
Schematic Reference
Hybrid Energy Storage Schematics
Connector End View Reference
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
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.
- Using the scan tool verify the hybrid battery pack cooling fan operates and there are no airflow obstructions near the battery pack.
- 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°C (7.2°F) of each other.
| ⇒ | If the fan does not operate refer to DTC P0A81-P0A83 |
| ⇒ | 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. |
Circuit/System Testing
Important: Use the following list to identify the appropriate terminals to test:
| • | Battery 1 Temperature Sensor Terminals 3 and 4 |
| • | Battery 2 Temperature Sensor Terminals 5 and 6 |
| • | Battery 3 Temperature Sensor Terminals 7 and 8 |
| • | Battery 4 Temperature Sensor Terminals 13 and 14 |
| • | Battery 5 Temperature Sensor Terminals 15 and 16 |
| • | 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:
| • | J-35616-65B for female terminals |
| • | J-35616-64B for male terminals |
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.
- Ignition OFF, disconnect harness connector X1 from the BECM. Refer to Hybrid Battery Service Disconnect/Connect
- Test for 10.5-11.5k ohms between the applicable temperature sensor circuit terminals.
- If all circuits test normal, replace the BECM.
| ⇒ | 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. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
