|EGR check valve (diagnostic
The 1996 and newer cars added a 2nd EGR test, called the Check monitor.
This valve allows testing the EGR main, and bypasses the normal EGR activation paths.
I call it VSV2 rear, the other valve is VSV1 in the front of the engine.
The bad part of the vavle is it adds more parts to fail , if this valve sticks open, the engine stalls.
The test procedures.
1. Disconnect vacuum hoses from EGR system check solenoid. See photo.
2. Turn ignition off. Disconnect EGR system check solenoid harness connector. Using an
ohmmeter, measure resistance between solenoid terminals. Resistance should be 37-44 ohms at
68°F (20°C) if the coil reads infinity , the coil and valve is bad. replace it now.
3.Disconnect vacuum hoses from EGR system check solenoid. Blow into port "A". Air should
pass through port "B" and not port "C". If Test passes, go to the next step. If Test fails
, replace EGR system check solenoid. Retest system.
4.Using fused jumper wires, connect a 12-volt battery to solenoid terminals. Blow into port "A".
Air should pass through filter and not port "B". If this test passes, check EGR system
check solenoid harness for open or short. Repair as necessary.
If wiring is good from this valve to ECU and vacuum lines are good.
the ECU could be bad. (ECU's never fail here)
1996 actual, Geo Tracker.