Hybrid Electric Vehicle (HEV) Battery Cooling System Performance

This code means that the system meant to keep the battery cool is not working right, which can cause the battery to overheat and not work efficiently.

The control module monitors the temperature of the HEV battery and the cooling system operation. When the temperature rises above 65°C (149°F) for a duration of more than 5 seconds without proper cooling response, this code gets triggered.

Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.

1. 11. Check the HEV coolant level—ensure it’s at the recommended level. Decision: Is coolant level low? If yes, top off and retest. If no, proceed to step 2.
2. 22. Inspect all wiring and connectors related to the battery cooling system for damage or corrosion. Decision: Are any issues found? If yes, repair and retest. If no, proceed to step 3.
3. 33. Test the battery coolant temperature sensor with a multimeter; it should show resistance values matching the manufacturer specifications (commonly around 2,500 ohms at 25°C/77°F). Decision: Is the sensor reading correct? If no, replace the sensor and retest. If yes, proceed to step 4.
4. 44. Check the operation of the coolant pump; it should activate when the battery temperature exceeds 40°C (104°F). Use a scan tool to monitor live data. Decision: Is the pump not operating? If no, replace the pump and retest. If yes, proceed to step 5.
5. 55. Inspect the coolant ducts for any obstructions. Ensure that airflow is unobstructed. Decision: Are ducts clear? If no, clean or repair as necessary and retest. If yes, further diagnosis may be needed.

• Low coolant level in the HEV battery cooling system
• Faulty cooling pump or fan
• Blocked or damaged cooling ducts
• Worn or failed battery coolant temperature sensor
• Wiring issues (shorts, opens) in the cooling system circuitry

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