P2420 code meaning
EVAP System Switching Valve Control Circuit High
Powertrain system Generic code P24xx codes Check engine light
What P2420 means
P2420 means the control circuit of the EVAP switching valve reads high - typically a short to battery voltage on the control line or an overcurrent detected by the driver stage. Karma lists P2420 for the rear fuel tank isolation valve of the Revero and GS-6, which the ECM operates, and Subaru's bulletin 09-103-23 for 2015 Legacy/Outback with an evaporative leak check module (ELCM) includes P2420 among the codes to check alongside the pump fault P2404. Ford instead reports all circuit faults of its switching valve as P2418. CARB requires output components to be monitored for circuit faults. P2419 is the low-side fault and P2418 the open circuit. The evap leak monitor cannot run until the circuit is repaired.
P2420 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2420
- Check engine light
- EVAP readiness not set
- No noticeable driveability change
Common causes of P2420
- Most likelyControl wire shorted to battery voltage
- PossibleSwitching valve coil with too low resistance (overcurrent)
- Less likelyFaulty driver stage in the ECM
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
EVAP switching valveEVAP leak detection pumpValve wiring
What each part of P2420 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| 20 | The exact fault in that area. |
What to do next
- Note P2420 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2420
What does P2420 mean?
P2420 means "EVAP System Switching Valve Control Circuit High". P2420 means the control circuit of the EVAP switching valve reads high - typically a short to battery voltage on the control line or an overcurrent detected by the driver stage. It is a generic code, so it means the same on every make.
Is it safe to drive with P2420?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P2420 fail an emissions test?
Yes, it can. P2420 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2420 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P2420 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.