P0078

P0078, P0084 EVT CONTROL SOLENOID VALVE

Description






Exhaust valve timing control solenoid valve is activated by ON/OFF
pulse duty (ratio) signals from the ECM.
The exhaust valve timing control solenoid valve changes the oil amount and direction of flow through exhaust valve timing control unit or stops oil flow.
The longer pulse width retards valve angle.
The shorter pulse width advances valve angle.
When ON and OFF pulse widths become equal, the solenoid valve stops oil pressure flow to fix the exhaust valve angle at the control position.


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 .
NO- INSPECTION END


Diagnosis Procedure


1. CHECK EXHAUST VALVE TIMING CONTROL SOLENOID VALVE POWER SUPPLY CIRCUIT

1.Turn ignition switch OFF.
2.Disconnect exhaust valve timing (EVT) control solenoid valve harness connector.
3.Turn ignition switch ON.
4.Check the voltage between EVT control solenoid valve harness connector and ground.





Is the inspection result normal?
YES- GO TO 3.
NO- GO TO 2.

2. DETECT MALFUNCTIONING PART

Check the following.
- Harness connectors E10, F10
- Harness for open or short between EVT control solenoid valve and IPDM E/R
- Repair open circuit, short to ground or short to power in harness or connectors.

3. CHECK EVT CONTROL SOLENOID VALVE OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.Turn ignition switch OFF.
2.Disconnect ECM harness connector.
3.Check the continuity between EVT control solenoid valve 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 4.
NO- Repair open circuit, short to ground or short to power in harness or connectors.

4. CHECK EVT CONTROL SOLENOID VALVE

.
Is the inspection result normal?
YES- GO TO 5.
NO- Replace malfunctioning EVT control solenoid valve. Exploded View.

5. CHECK INTERMITTENT INCIDENT

Intermittent Incident.
- INSPECTION END


Component Inspection


1. CHECK EXHAUST VALVE TIMING CONTROL SOLENOID VALVE-I

1.Turn ignition switch OFF.
2.Disconnect exhaust valve timing control solenoid valve harness connector.
3.Check resistance between exhaust valve timing control solenoid valve terminals as per the following.





Is the inspection result normal?
YES- GO TO 2.
NO- Replace malfunctioning exhaust valve timing control solenoid valve. Exploded View.

2. CHECK EXHAUST VALVE TIMING CONTROL SOLENOID VALVE-II

1.Remove exhaust valve timing control solenoid valve. Exploded View.





2.Provide 12 V DC between exhaust valve timing control solenoid valve terminals 1 and 2, and then interrupt it. Check that the plunger moves as shown in the figure.

CAUTION:
Do not apply 12 V DC continuously for 5 seconds or more.
Doing so may result in damage to the coil in exhaust valve timing control solenoid valve.
NOTE:
Always replace O-ring when exhaust valve timing control solenoid valve is removed.
Is the inspection result normal?
YES- INSPECTION END
NO- Replace malfunctioning exhaust valve timing control solenoid valve. Exploded View.