DTC 0311

COMPONENT DESCRIPTION
The vacuum cut valve and vacuum cut valve bypass valve are installed in parallel on the EVAP purge line between the fuel tank and the EVAP canister.
The vacuum cut valve prevents the intake manifold vacuum from being applied to the fuel tank.
The vacuum cut valve bypass valve is a solenoid type valve and generally remains closed. It opens only for on board diagnosis. The vacuum cut valve bypass valve responds to signals from the ECM. When the ECM sends an ON (ground) signal, the valve is opened. The vacuum cut valve is then bypassed to apply intake manifold vacuum to the fuel tank.






EVAPORATIVE EMISSION SYSTEM DIAGRAM






CONSULT REFERENCE VALUE IN DATA MONITOR MODE
Specification data are reference values.






ECM TERMINALS AND REFERENCE VALUE
Specification data are reference values and are measured between each terminal and (25) (ECCS ground).






ON BOARD DIAGNOSIS LOGIC


DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE

CAUTION: Always drive vehicle at a safe speed.

NOTE: If "DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE" has been previously conducted, always turn ignition switch "OFF" and wait at least 5 seconds before conducting the next test.

TESTING CONDITION:
This test may be conducted with the drive wheels lifted in the shop or by driving the vehicle. If a road test is expected to be easier, it is unnecessary to lift the vehicle.
Always perform test at a temperature of 5 to 30° C (41 to 86° F).


Without TOOLS






OVERALL FUNCTION CHECK
1) Remove vacuum cut valve and vacuum cut valve bypass valve as an assembly.
2) Apply vacuum to port (A) and check that there is no suction from port (B).
3) Apply vacuum to port (B) and check that there is suction from port (A).
4) Blow air in port (B) and check that there is a resistance to flow out of port (A).
5) Supply battery voltage to the terminal.
6) Blow air in port (A) and check that air flows freely out of port (B).
7) Blow air in port (B) and check that air flows freely out of port (A).






DIAGNOSTIC PROCEDURE

COMPONENT INSPECTION
Vacuum cut valve bypass valve
Check air passage continuity.









With CONSULT
Perform "VC/V BYPASS/V" in "ACTIVE TEST" mode.
If NG, replace vacuum cut valve bypass valve.


- - - OR - - -









Without TOOLS
If NG, replace vacuum cut valve bypass valve.







Vacuum cut valve
Check vacuum cut valve as follows:
1. Plug port (C) and (D) with fingers.
2. Apply vacuum to port (A) and check that there is no suction from port (B).
3. Apply vacuum to port (B) and check that there is suction from port (A).
4. Blow air in port (B) and check that there is a resistance to flow out of port (A).
5. Open port (C) and (D).
6. Blow air in port (A) check that air flows freely out of port (C).
7. Blow air in port (B) check that air flows freely out of port (D).