Toyota Sienna Service Manual: Evaporative Emission System Reference Orifice

DTC SUMMARY

HINT:

The 0.02 inch orifice is located inside the pump module.

DESCRIPTION

The circuit description can be found in the EVAP (Evaporative Emission) System (See page ES-409).

INSPECTION PROCEDURE

Refer to the EVAP System (See page ES-412).

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 35°C (95°F) 5 hours after the ignition switch is turned off, the monitor check starts 2 hours later. If it is still not below 35°C (95°F) 7 hours after the ignition switch is turned off, the monitor check starts 2.5 hours later.

*2: If there is only a small amount of fuel in the fuel tank, stabilizing the EVAP pressure takes longer than usual.

The leak detection pump creates negative pressure through the reference orifice. When the system is normal, the EVAP pressure is in 724 to 752 mmHg* and saturated within a minute.

If not, the ECM interprets this as a malfunction. The ECM will illuminate the MIL and set DTC if this malfunction is detected in consecutive drive cycle.

*: Typical valve

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

Key-off monitor sequence 1 to 8

TYPICAL MALFUNCTION THRESHOLDS

MONITOR RESULT

Refer to CHECKING MONITOR STATUS (See page ES-19).