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 found a problem with the electric pump that helps move the transmission fluid. It's like if a toy's motor wasn't working because the wires were disconnected.
The P0C20 code indicates an issue with the electrical circuit that controls the phases (U, V, W) of the electric or auxiliary transmission fluid pump. This can cause the pump to malfunction or stop working.
The electric/auxiliary transmission fluid pump is responsible for circulating transmission fluid in certain hybrid or electric vehicles. The pump is controlled by a three-phase electrical circuit (U, V, W). An open circuit in any of these phases can prevent the pump from operating correctly, leading to potential transmission performance issues.
• Transmission overheating
• Poor transmission performance
• Warning light on the dashboard
• Unusual noises from the transmission area
• Open or shorted wiring in the pump circuit
• Faulty electric/auxiliary transmission fluid pump
• Blown fuse or faulty relay
• Corroded or damaged connectors
Transmission: A system in a vehicle that transmits power from the engine to the wheels.
Circuit: A complete and closed path around which a circulating electric current can flow.
• Check for any blown fuses related to the transmission pump circuit.
• Inspect the wiring and connectors for damage or corrosion.
• Test the electric/auxiliary transmission fluid pump for proper operation.
• Replace any blown fuses and test the circuit.
• Repair or replace damaged wiring or connectors.
• Replace the electric/auxiliary transmission fluid pump if faulty.
• Multimeter
• OBD-II scanner
• Basic hand tools
$200 - $800
Moderate
• Toyota Prius
• Chevrolet Volt
• Ford Fusion Hybrid
• Regularly inspect wiring for wear and tear.
• Ensure connectors are clean and secure.
• Perform routine maintenance checks on the transmission system.
Electrical Circuit Issue
• Avoid driving long distances until the issue is fixed to prevent transmission damage.
• Seek professional diagnostic and repair services.
Check with your manufacturer, as transmission components may be covered under powertrain warranties.
This code is more common in hybrid and electric vehicles due to their reliance on electric pumps for transmission fluid circulation.
Moderate – Addressing this issue promptly can prevent further transmission damage.
Driving with a malfunctioning transmission fluid pump can lead to transmission failure, which may result in unsafe driving conditions.
• Vehicle at operating temperature
• Transmission in various gears
The electric/auxiliary transmission fluid pump is typically located near the transmission housing or integrated within it.
Q: Can I drive with a P0C20 code?
A: It's not recommended to drive long distances with this code active, as it may lead to transmission damage.
Q: How can I reset the P0C20 code?
A: After repairs, you can use an OBD-II scanner to clear the code, but ensure the issue is resolved first.
High-End · Full-system diagnostics
A full-system bidirectional platform aimed at advanced DIY users and professional diagnostic workflows.
Network faults often require full-system access instead of a generic code reader alone.
View on Amazon
Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
View on Amazon
Universal · Wire connectors and repair kit
Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.