P0078

P0078, P0084 EVT CONTROL MAGNET RETARDER





Description





Exhaust valve timing control magnet retarder (1) controls the shut/open timing of the exhaust valve by ON/OFF pulse duty signals sent from the ECM.
The longer pulse width retards valve timing.
The shorter pulse width advances valve timing.




DTC Logic

DTC DETECTION LOGIC






DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
- GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
1. Start engine and let it idle for 5 seconds.
2. Check 1st trip DTC.
Is 1st trip DTC detected?
YES - Go to P0078.
NO - INSPECTION END




Diagnosis Procedure
Regarding Wiring Diagram information, Electrical Diagrams.
1.CHECK EXHAUST VALVE TIMING (EVT) CONTROL MAGNET RETARDER POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect EVT control magnet retarder harness connector.
3. Turn ignition switch ON.





4. Check the voltage between EVT control magnet retarder harness connector and ground.





Is the inspection result normal?
YES - GO TO 2.
NO - Repair open circuit, short to ground or short to power in harness or connectors.
2.CHECK EVT CONTROL MAGNET RETARDER OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between EVT control magnet retarder harness connector and ECM harness connector.





4. Also check harness for short to ground and short to power.
Is the inspection result normal?
YES - GO TO 3.
NO - Repair open circuit, short to ground or short to power in harness or connectors.
3.CHECK EVT CONTROL MAGNET RETARDER
P0014.
Is the inspection result normal?
YES - GO TO 5.
NO - GO TO 6.
4.REPLACE EVT CONTROL MAGNET RETARDER
1. Replace malfunctioning EVT control magnet retarder.
2. Perform Special Repair Requirement.
- INSPECTION END
5.CHECK INTERMITTENT INCIDENT
Intermittent Incident.
- INSPECTION END




Component Inspection
1.CHECK EXHAUST VALVE TIMING CONTROL MAGNET RETARDER
1. Turn ignition switch OFF.
2. Disconnect exhaust valve timing control magnet retarder harness connector.





3. Check resistance between exhaust valve timing control magnet retarder terminals as per the following.





Is the inspection result normal?
YES - INSPECTION END
NO - GO TO 2.
2.REPLACE EXHAUST VALVE TIMING CONTROL MAGNET RETARDER
1. Replace malfunctioning exhaust valve timing control magnet retarder.
2. Perform Special Repair Requirement.
- INSPECTION END