Powertrain, generic (extended)

P2420 EVAP System Switching Valve Control Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

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.

Likely causes

Control wire shorted to battery voltage
Switching valve coil with too low resistance (overcurrent)
Faulty driver stage in the ECM

Symptoms

  • Check engine light
  • EVAP readiness not set
  • No noticeable driveability change

Repair estimate

DifficultyMediumDIY possible
Parts and labour€40–450
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

evap switching valveevap leak detection pumpvalve wiring

Related codes

P2418P2419P2404P2402

References: law.cornell.edu, static.nhtsa.gov, static.nhtsa.gov.