Inspection Procedure Using OBDII Scan Tool

CIRCUIT DESCRIPTION
The ECM turns on a VSV (Vacuum Switching Valve) to draw the air into the diaphragm chamber of the pressure regulator if it detects that the temperature of the engine coolant is too high during engine starting.
The air drawn into the chamber increases the fuel pressure to prevent fuel vapor lock at high engine temperature in order to help the engine start when it is warm.
Fuel pressure control ends approx. 120 sec. after the engine is started.





WIRING DIAGRAM











INSPECTION PROCEDURE





1. INSPECT VSV OPERATION WITH COLD ENGINE
(a) The engine coolant temperature should be below 47°C (117°F).
(b) Check that the vacuum gauge indicates zero at 2,500 rpm.
(c) Check that the EGR pipe is not hot.

2. INSPECT OPERATION OF VSV AND EGR VACUUM MODULATOR WITH HOT ENGINE
(a) Warm up the engine to above 53°C (127°F).
(b) Check that the vacuum gauge indicates low vacuum at 2,500 rpm.





3. INSPECT VSV FOR OPEN CIRCUIT
Using an ohmmeter, check that there is continuity between the terminals.

Resistance: At 20°C (68°F) 30 - 34 ohm

If there is no continuity, replace the VSV.





4. INSPECT VSV FOR GROUND
Using an ohmmeter, check that there is no continuity between each terminal and the body.
If there is continuity, replace the VSV.

5. INSPECT VSV OPERATION





(a) Check that the air flows from port G to E.





(b) Apply battery voltage across the terminals.
(c) Check that the air does not flows from port G to E.
If operation is as specified, replace the VSV.

6. RECONNECT VACUUM HOSES AND CONNECTOR