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 a part in the car that helps control air and gases inside the engine. It's like a valve that isn't working right, and it's important for keeping the engine running smoothly.
The P120C code is triggered when the engine control module (ECM) detects an open circuit in the crankcase ventilation diagnostic valve. This valve is crucial for managing the flow of gases from the crankcase to prevent pressure build-up.
The crankcase ventilation diagnostic valve is part of the Positive Crankcase Ventilation (PCV) system. It helps recycle gases from the engine's crankcase back into the intake manifold to be burned again. An open circuit indicates a break in the electrical connection, preventing the valve from functioning properly.
• Check Engine Light illuminated
• Rough engine idle
• Decreased fuel efficiency
• Faulty crankcase ventilation diagnostic valve
• Damaged wiring or connectors
• Blown fuse related to the valve circuit
Crankcase: The part of the engine that houses the crankshaft.
PCV System: Positive Crankcase Ventilation system, which reduces emissions by recycling gases.
• Use an OBD-II scanner to verify the code.
• Inspect the crankcase ventilation valve and its wiring for damage.
• Check for any blown fuses related to the valve circuit.
• Replace the faulty crankcase ventilation diagnostic valve.
• Repair or replace damaged wiring or connectors.
• Replace any blown fuses.
• OBD-II scanner
• Multimeter
• Socket set
$100 - $300
Moderate
• Volkswagen Jetta
• Audi A4
• BMW 3 Series
• Regularly inspect the PCV system.
• Ensure proper maintenance of electrical connections.
• Replace components as recommended by the manufacturer.
Sensor Issue
• Have the vehicle inspected by a professional if the Check Engine Light is on.
• Avoid driving with a known issue in the PCV system to prevent further damage.
Check with the vehicle manufacturer for warranty coverage on emissions-related components.
The P120C code has been associated with vehicles using advanced PCV systems to meet emissions standards.
Moderate – It's important to address this issue to maintain engine performance and emissions compliance.
Driving with a malfunctioning PCV system can lead to increased emissions and potential engine damage.
• Engine at operating temperature
• Vehicle at idle
The crankcase ventilation diagnostic valve is typically located near the engine's intake manifold or valve cover.
Q: Can I drive with a P120C code?
A: It's not recommended to drive for extended periods with this code, as it can lead to engine performance issues.
Q: How can I prevent a P120C code?
A: Regular maintenance and inspection of the PCV system can help prevent this code.
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