• Check engine light illuminated
• Reduced vehicle performance
• Possible overheating warning
• Faulty temperature sensor
• Wiring issues or poor connections
• Actual overheating of the drive motor
PCM: Powertrain Control Module
BECM: Battery Energy Control Module
• P1B78
• P1B80
This code means the car's computer thinks the temperature sensor for the electric motor is reading too high, like if a thermometer said it was really hot when it wasn't.
The vehicle's control module has detected an unusually high temperature reading from the secondary temperature sensor in the drive motor 'A' circuit.
The P1B79 code is triggered when the Powertrain Control Module (PCM) or the Battery Energy Control Module (BECM) detects an implausibly high temperature reading from the secondary temperature sensor associated with the drive motor 'A'. This could indicate a fault in the sensor circuit, a wiring issue, or an actual overheating condition.
• Verify the code with an OBD-II scanner
• Inspect the wiring and connections to the temperature sensor
• Test the temperature sensor for proper operation
• Replace the faulty temperature sensor
• Repair or replace damaged wiring
• Ensure proper cooling of the drive motor
• OBD-II scanner
• Multimeter
• Basic hand tools
$100 - $300
Moderate
• Chevrolet Volt
• Nissan Leaf
• Toyota Prius
• Regular maintenance and inspection of the cooling system
• Ensure proper installation of sensors
• Monitor vehicle performance for early signs of issues
Sensor Issue
• Do not ignore the check engine light; have it checked promptly.
• Avoid driving the vehicle if overheating is suspected.
• Regularly service the vehicle to prevent sensor issues.
Check with your vehicle manufacturer as sensor issues may be covered under warranty.
This code is relatively common in hybrid and electric vehicles, where precise temperature management is crucial.
Moderate – While the vehicle may still operate, ignoring this issue could lead to more severe problems.
Driving with a malfunctioning temperature sensor can lead to overheating and potential engine damage.
• Vehicle at operating temperature
• All electrical connections secure
The temperature sensor is typically located near the drive motor or integrated within the motor housing.
Q: Can I drive with a P1B79 code?
A: It's not recommended to drive for extended periods as it may lead to overheating.
Q: How do I reset the P1B79 code?
A: After repairs, use an OBD-II scanner to clear the code. If the issue persists, further diagnosis is needed.