Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means there's a problem with the car's battery system where it can't keep the electricity inside safely, like a balloon with a hole letting air out.
The code indicates a fault in the external isolation of the hybrid or electric vehicle's battery voltage system.
P2C85 is triggered when the vehicle's control module detects an issue with the isolation of the battery voltage from the vehicle's chassis. This isolation is crucial to prevent electrical shorts and ensure safety. The fault may be due to a breakdown in the insulation or a failure in the monitoring system.
• Warning light on the dashboard
• Reduced vehicle performance
• Inability to charge the battery
• Damaged battery insulation
• Faulty voltage isolation monitor
• Corroded or damaged connectors
Isolation: The process of keeping electrical components separate to prevent shorts.
Insulation: Material used to prevent the passage of electricity.
• Inspect the battery insulation for damage.
• Check the voltage isolation monitor for faults.
• Examine connectors and wiring for corrosion or damage.
• Replace damaged battery insulation.
• Repair or replace faulty isolation monitor.
• Clean or replace corroded connectors.
• Multimeter
• Insulation tester
• Diagnostic scanner
$200 - $800
Moderate
• Toyota Prius
• Chevrolet Volt
• Nissan Leaf
• Regularly inspect battery insulation.
• Ensure connectors are clean and secure.
• Schedule routine maintenance checks.
Electrical System Issue
• Avoid driving the vehicle until repaired.
• Contact a certified technician for diagnosis.
• Do not attempt DIY repairs on high-voltage systems.
Check with the manufacturer for battery and electrical system coverage.
This code has become more common with the increase in hybrid and electric vehicles, highlighting the importance of battery isolation for safety.
High – This issue can lead to safety hazards and should be addressed immediately.
Handling high-voltage systems can be dangerous. Only qualified professionals should perform repairs.
• Vehicle in 'On' mode
• Battery system under load
The battery and its associated components are usually located in the rear or under the vehicle.
Q: Can I drive my car with this code?
A: It is not recommended to drive the vehicle as it may pose safety risks.
Q: How do I reset the code?
A: The code can be reset using a diagnostic scanner, but the underlying issue must be fixed first.
Pro · Four-system diagnostics
A handheld scanner aimed at engine, transmission, ABS, and airbag diagnostic work.
Chassis and ABS faults usually need a scanner that can read brake-system data directly.
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Universal · Torque wrench
Useful when reassembly torque matters for wheel, suspension, and under-hood fasteners.
Useful when wheel, hub, or suspension hardware needs correct reassembly torque.
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Universal · Drive-on ramps
Helpful for safer access underneath the vehicle during exhaust, EVAP, and underbody inspection work.
Helpful for safer access during underbody inspection work.
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