P0022

DTC P0012 "A" CAMSHAFT POSITION-TIMING OVER-RETARDED (BANK 1)
DTC P0022 "A" CAMSHAFT POSITION-TIMING OVER-RETARDED (BANK 2)

Component Location:

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
Figure 1. Illustrates the method for detecting unresolved phasing steady-state error.

The figure shows two cases, case 1 to the left of the dashed line, and case 2 to the right of the dashed line.

In case 1, the duty cycle command is considered high, or above a calibration threshold memorized in PCM. This should cause the cam phaser to move toward the maximum position, but the position remains at a medium level. The range of positions considered 'medium' is defined by calibrations.

In case 2, the duty cycle command is considered low, or below a calibration threshold memorized in PCM. This should cause the cam phaser to move toward the minimum position, but the position remains at a medium level.

Each of these cases is a phaser position error failure. Each case is also considered to be due to a phaser seizure. When either case is detected, a timing counter begins to increment. If the counter exceeds a calibration threshold memorized in PCM, the failure criteria is TRUE.

Another similar diagnostic test is performed to check steady-state error. In this test, no consideration is given to the duty cycle command versus phaser position. This test is only a check of the phasing position error. In the test, if the phaser error is greater than a calibration threshold memorized in PCM, a timing counter increments. If the counter exceeds the calibration threshold memorized in PCM.the failure criteria is TRUE.

PCM monitors CAM phaser error while both cam offset is available and cam velocity is below 15 CAD/S. If cam phaser does not move although PCM commands OCV duty cycle PCM determines that a fault exists and a DTC is stored.

DTC Detecting Condition:

Schematic Diagram:

SIGNAL WAVEFORM AND DATA

Signal Waveform And Data:

This example shows a typical Crankshaft Position Sensor (CKPS) and Camshaft Position Sensor (CMPS) waveform at idle. If the Cam Phasing is generated by PCM, the offset of cam target wheel tooth varies against 58X reference tooth of CKPS. Cam phasing can be detected from offset variation.




MONITOR SCANTOOL DATA
1. Connect scantool and ENG "ON".
2. Monitor "CMPS (B1/B2)" on the service data.
3. Are the "CMPS (B1)" data displayed correctly?

YES - Fault is intermittent caused by poor contact in the sensor's and/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
1. Check oil level is O.K.
2. Check oil is contaminated.
3. 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
1. Connect scantool and IG "ON"




2. Select "OCV" on the Actuation Test
3. Activate "OCV" by pressing "STRT (F1)" key
(should hear a faint click from Oil Control solenoid Valve)

4. Repeat this procedure 4 or 5 times to ensure reliability
5. 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.