Code 0801

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 OBD.
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




DIAGNOSTIC CHART
Procedure for malfunction A




DIAGNOSTIC CHART
Procedure for malfunction B




DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE
Perform "Procedure for malfunction A" first. If DTC cannot be confirmed, perform "OVERALL FUNCTION CHECK", "Procedure for malfunction B".

Procedure for malfunction A
CONSULT
1) Turn ignition switch "ON".
2) Select "DATA MONITOR" mode with CONSULT.
3) Wait for at least 5 seconds.

OR

GST
1) Turn ignition switch "ON" and wait for at least 5 seconds.
2) Select "MODE 3" with GST.

OR

NO TOOLS
1) Turn ignition switch "ON" and wait for at least 5 seconds.
2) Perform "Diagnostic Test Mode II (Self-diagnostic results)" with ECM.

OVERALL FUNCTION CHECK
Procedure for malfunction B
1) Remove vacuum cut valve and vacuum cut valve bypass valve as an assembly.
2) Apply vacuum to port (A) and ensure that there is no suction from port (B).
3) Apply vacuum to port (B) and ensure that there is suction from port (A).
4) Blow air in port (B) and ensure 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 ensure free flow out of port (B).
7) Blow air in port (B) and ensure free flow out of port (A).

COMPONENT INSPECTION
Vacuum cut valve bypass valve




Check air passage continuity.




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 ensure that there is no suction from port (B).
3. Apply vacuum to port (B) and ensure that there is suction from port (A).
4. Blow air in port (B) and ensure that there is a resistance to flow out of port (A).
5. Open port (C) and (D).
6. Blow air in port (A) and ensure free flow out of port (C).
7. Blow air in port (B) and ensure free flow out of port (D).




WIRING DIAGRAM