P0021

DTC P0021






GENERAL DESCRIPTION
Different from the existing fixed cam phase angle type, CVVT(Continuously Variable Valve Timing) is the device which varies cam phase angle continuously to be optimum. And with engine oil pressure, it operates. CVVT consists of OCV(Oil Control Valve) and cam phaser. OCV, mounted on cylinder head, controls the amount and direction of oil delivered to cam phaser by oil valve which is connected to a solenoid. Cam phaser, rotating cam phaser rotor with pressure and amount of oil produced by OCV, rotates cam shaft forcefully for or against the rotating direction and finally, cam shaft phase changes. With the appliance of CVVT, engine power,fuel efficiency and the quality of exhaust gas are improved.

DTC DESCRIPTION
PCM detects CAM phasing average rate while cam offset is available. If the CAM phasing rate is failure in 12 times out of 15 CAM phasing test PCM determines that a fault exists and a DTC is stored.

DTC Detecting Condition:

DTC DETECTING CONDITION

Signal Waveform And Data:

SIGNAL WAVEFORM AND DATA

Schematic Diagram:

SCHEMATIC DIAGRAM

MONITOR SCANTOOL DATA
1. connect Scantool and ENG "ON"




2. Monitor "CMPS(B2)" on the service data.
3. Are the "CMPS(B2)" data displayed correctly?

YES - Fault is intermittent caused by poor contact in the sensor`sand/or PCM`s connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection,bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.

NO - Go to "System Inspection" procedure.

SYSTEM INSPECTION
1. Visual Inspection
a. Check oil level is O.K.
b. Check oil is contaminated.
c. Check that any oil leakage or blockage is occurred on the parts related to CVVT.
d. Has a problem been found?

YES - Repair or replace as necessary and then, go to " Verification of Vehicle Repair" procedure.

NO - Go to "Component Inspection" procedure.

COMPONENT INSPECTION
1. Check OCV
a. Connect Scantool and IG "ON"
b. Select "OCV" on the Actuation Test
c. Activate "OCV" by pressing "STRT(F1)" key(should hear a faint click from Oil Control solenoid Valve)




d. Repeat this procedure 4 or 5 times to ensure reliability
e. Has a problem been found?

YES - Substitute with a known - good OCV and check for proper operation. If the problem is corrected, replace OCV and go to "Verification of Vehicle Repair" procedure.

NO - Substitute with a known - good CVVT and check for proper operation. If the problem is corrected, replace CVVT and go to "Verification of Vehicle Repair" procedure.

VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has been corrected.
1. Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code(DTC) which has been diagnosed.
2. Using a Scantool, Clear the DTCs
3. Operate the vehicle within conditions noted in the freeze frame data or enable conditions
4. Monitor that all readiness test have been verified as "Complete".
5. Are any DTCs present?

YES - Go to the applicable troubleshooting procedure.

NO - System is performing to specification at this time.