EVAP System Switching Valve Control Circuit High
The P2420 code indicates that the Powertrain Control Module (PCM) has detected a high voltage condition in the control circuit of the Evaporative Emission (EVAP) system switching valve. This valve is responsible for directing fuel vapor flow between the canister and the intake manifold. A high voltage reading typically suggests a short to power, an open circuit, or a faulty valve solenoid. This can prevent proper EVAP system operation, potentially causing a fuel vapor leak and increased emissions.
1. Most Common Causes
- Faulty EVAP switching valve solenoid
- Short to power in the valve control circuit
- Open or damaged wiring/connector
- Corroded electrical connector
- Failed PCM (rare)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Possible fuel odor
- Failed emissions test
- Rough idle or poor fuel economy (less common)
3. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve all codes and freeze frame data.
Step 2: Visually inspect the EVAP switching valve and its wiring/connector for damage, corrosion, or loose connections.
Step 3: Test the valve solenoid resistance with a multimeter (compare to specs, typically 20-40 ohms).
Step 4: Check for voltage at the valve connector with key on; should be battery voltage on one pin and ground on the other when commanded.
Step 5: If voltage is present but valve doesn't click, replace the valve. If no voltage, trace circuit for shorts or opens.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, it is generally safe to drive short distances, but the vehicle may fail an emissions test and fuel vapor leaks could occur. It's best to diagnose and repair promptly.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts and labor, depending on the cause. A new EVAP switching valve costs around $20-$60, and labor is usually 0.5-1 hour.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.