Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car's computer has detected a problem with the fan that cools the battery in a hybrid or electric vehicle. It's like when a fan in your computer stops working properly, and things can get too hot.
The vehicle's control module has detected a high voltage or resistance in the circuit that controls the cooling fan for the hybrid or electric vehicle's battery pack.
The P0D66 code is triggered when the Powertrain Control Module (PCM) or Battery Energy Control Module (BECM) detects an abnormally high voltage condition in the circuit responsible for enabling the battery pack cooling fan. This could be due to a short circuit, open circuit, or a faulty fan motor.
• Illuminated check engine light
• Overheating of the battery pack
• Reduced vehicle performance
• Faulty battery cooling fan
• Open or shorted wiring in the cooling fan circuit
• Faulty fan relay or control module
PCM: Powertrain Control Module
BECM: Battery Energy Control Module
• Inspect the cooling fan and its wiring for damage.
• Check the fan relay and control module for proper operation.
• Use a multimeter to test the voltage and resistance in the fan circuit.
• Replace the faulty cooling fan.
• Repair or replace damaged wiring or connectors.
• Replace the fan relay or control module if necessary.
• OBD-II scanner
• Multimeter
• Screwdriver set
$150 - $500
Moderate
• Toyota Prius
• Chevrolet Volt
• Nissan Leaf
• Regularly inspect the cooling fan and its components.
• Ensure proper maintenance of the vehicle's electrical system.
• Avoid exposing the vehicle to extreme temperatures.
Electrical Circuit Issue
• Avoid driving the vehicle until the issue is resolved to prevent battery damage.
• Consult a professional mechanic for accurate diagnosis and repair.
Check with the vehicle manufacturer for warranty coverage on hybrid/EV components.
This code has been more common with the increased use of hybrid and electric vehicles, as battery cooling is crucial for their performance.
High – This issue can lead to battery damage if not addressed promptly.
Driving with an overheated battery can be dangerous, and ignoring this code may void the vehicle's warranty.
• Vehicle must be running.
• Battery pack must be at operating temperature.
The cooling fan is typically located near the battery pack, often in the rear of the vehicle.
Q: Can I drive my car with this code?
A: It's not recommended, as overheating the battery can cause damage.
Q: How can I prevent this issue?
A: Regular maintenance and inspections can help catch issues before they become serious.
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