P2420: Evaporative Emission System Switching Valve Control Circuit High
What to do
The car drives normally. If several evaporative valves are reporting together, ask for their shared fuse and supply to be checked rather than each valve replaced.
What this code means
The switching valve control circuit reads above its valid range — an open circuit, a short to supply, or a solenoid winding that has gone open. The supply and fuse are the cheap checks, and a failed supply produces identical codes across several evaporative valves at once, which is one fault rather than several.
Likely causes
Start here
- Open circuit in valve wiring · moderate
- Faulty EVAP switching valve · moderate
- Corroded or loose connector · easy
Less common
- Blown fuse or failed supply · easy
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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