Toyota Sienna Service Manual: Evaporative Emission System Switching Valve Control Circuit High

DTC P2420 Evaporative Emission System Switching Valve Control Circuit High

DTC SUMMARY

DESCRIPTION

The circuit description can be found in the EVAP (Evaporative Emission) System.

INSPECTION PROCEDURE

Refer to the EVAP System.

MONITOR DESCRIPTION

5 hours*1 after the ignition switch is turned off, the electric vacuum pump creates negative pressure (vacuum) in the EVAP (Evaporative Emission) system. The ECM monitors for leaks and actuator malfunctions based on the EVAP pressure.

HINT: *1: If the engine coolant temperature is not below 35C (95F) 5 hours after the ignition switch is turned off, the monitor check starts 2 hours later. If it is still not below 35C (95F) 7 hours after the ignition switch is turned off, the monitor check starts 2.5 hours later.

*2: If only a small amount of fuel is in the fuel tank, it takes longer for the EVAP pressure to stabilize.

The vent valve turns ON (closes) and the EVAP (Evaporative Emission) system pressure is then measured by the ECM, using the pressure sensor, to conduct an EVAP leak check. If the pressure does not increase when the vent valve is open, the ECM interprets this as the vent valve being stuck open. The ECM illuminates the MIL and sets the DTC.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

Key-off monitor sequence 1 to 8

1. Atmospheric pressure measurement

2. First reference pressure measurement

3. EVAP canister vent valve close stuck check

4. Vacuum introduction

5. EVAP canister purge valve close stuck check

6. Second reference pressure measurement

7. Leak check

8. Atmospheric pressure measurement

TYPICAL MALFUNCTION THRESHOLDS

MONITOR RESULT

Refer to CHECKING MONITOR STATUS