Overall Function Check
ON-BOARD DIAGNOSIS LOGICIf the excess Exhaust Gas Recirculation (EGR) flow exists due to the EGRC-BPT valve malfunction, the engine roughness will be increased. If the roughness is large, then the vacuum to the EGR valve is interrupted through the EGR & canister control solenoid valve. If the engine roughness is reduced at that time, the EGRC-BPT valve malfunction is indicated.
OVERALL FUNCTION CHECK
Instead of performing DTC DETECTING CONDITION, the following method can be used for checking the EGRC-BPT valve function. (The "NG" of the OVERALL FUNCTION CHECK means the same as the DTC detection.)
1. Disconnect the rubber tube to intake manifold, which comes from fuel pressure regulator.
2. Disconnect the rubber tube to EGRC-BPT valve, which comes from EGR & canister control solenoid valve. Connect the intake manifold and the EGRC-BPT valve with rubber tube. (The intake manifold vacuum will be directly applied to the EGRC-BPT valve.)
3. Start engine.
4. Check for the EGR valve lifting when racing at lower than 1,500 rpm under no load. EGR valve should be closed and should not lift up.
5. Check the EGR valve lifting when racing from 2,000 rpm up to 3,500 rpm under no load. EGR valve should lift up and down without sticking.
6. Check rubber tube between EGR & canister control solenoid valve and throttle body for misconnection, cracks or obstruction.