DTC DETECTION LOGIC
DTC No. | Trouble diagnosis name (Trouble diagnosis content) | DTC detecting condition | Possible cause |
P0078 | EX V/T ACT/CIRCB1 (Exhaust valve timing control solenoid valve circuit) | An improper voltage is sent to the ECM through exhaust valve timing control solenoid valve. |
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DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.
>> GO TO2.
2.PERFORM DTC CONFIRMATION PROCEDURE
Is 1st trip DTC detected?
YES >> Proceed to EC, "Diagnosis Procedure".
NO >> INSPECTION END
1.CHECK EXHAUST VALVE TIMING CONTROL SOLENOID VALVE POWER SUPPLY
Is the inspection result normal?
YES >> GO TO 3.
NO >> GO TO 2.
2.CHECK EXHAUST VALVE TIMING CONTROL SOLENOID VALVE POWER SUPPLY CIRCUIT
4. Also check harness for short to ground.
Is the inspection result normal?
YES >> Perform the trouble diagnosis for power supply circuit.
NO >> Repair or replace errordetected parts.
3.CHECK EXHAUST VALVE TIMING CONTROL SOLENOID VALVE GROUND CIRCUIT
4. Also check harness for short to ground and to power.
Is the inspection result normal?
YES >> GO TO 4.
NO >> Repair or replace errordetected parts.
4.CHECK EXHAUST VALVE TIMING CONTROL SOLENOID VALVE
Check the exhaust valve timing control solenoid valve. Refer to EM, "Exploded View".
Is the inspection result normal?
YES >> Check intermittent incident. Refer to GI, "Intermittent Incident".
NO >> Replace exhaust valve timing control solenoid valve.
1.CHECK EXHAUST VALVE TIMING CONTROL SOLENOID VALVEI
Is the inspection result normal?
YES >> GO TO 2.
NO >> Replace exhaust valve timing control solenoid valve. Refer to EM, "Exploded View".
2.CHECK EXHAUST VALVE TIMING CONTROL SOLENOID VALVEII
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 Oring when exhaust valve timing control solenoid valve is removed.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Replace exhaust valve timing control solenoid valve. Refer to EM56, "Exploded View".
Exhaust valve timing control
Exhaust valve timing control : system diagram
Exhaust valve timing control : system description
INPUT/OUTPUT SIGNAL CHART
Sensor
Input signal to ECM
ECM function
Actuator
Crankshaft position sensor (POS)
Engine speed*1
Piston position
Exhaust valve timing c ...
Fender cover
FENDER COVER : Removal and Installation
REMOVAL
1. Fully open hood assembly.
2. Disengage pawls beginning at the front of the fender cover and
working toward the rear of vehicle and then remove front fender
cover.
CAUTION:
When performing the procedure after removing fender
cover, protect th ...