3.
Monitor "CAM(B2)" status on the service data.
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, controlls 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 exhause gas are improved.
Small particles in the engine oil may cause the oil control valve to bind or otherwise get stuck at certain spool positions. A test is used in this diagnostic to detect a stuck valve spool. A cleaning function is then used to try and free the spool. If unsuccessful, the diagnostic test is failed.
Figure 1. illustrates the principle of the valve stuck diagnostic test. As in the phaser error diagnostic illustration, there are two cases shown in the figure. The case on the left shows a case where the dutycycle is above a calibration threshold, yet the phaser position is near the minimum position. Under normal operation, such a duty cycle command would move the phaser toward its maximum position.The case on the right shows the opposite situation. The duty cycle command is below a threshold, yet the phaser position is near its maximum.
PCM monitors OCV stuck while cam offset is available and Valve cleaning is not in progress .If the PCM detects that CAM position angle is over 20 CAD(Crank Angle Degree) than expected cam positionthat PCM controls the OCV while cam position is in designated crank angle degree, PCM determines that a faultexists and a DTC is stored.
Item | Detecting Condition | Possible cause | |
DTC Strategy | ● Determines if oil control valve is stuck | ● Oil Pressure Loss ● OCV(B2) seizure ● PCM | |
Enable Conditions | ● Valve cleaning not in progress ● Offsets available | ||
Thresh old value | Case 1 | ● Cam position 〉 50 CAD ● Cam position Error 〉 20 CAD ● Timing counter 〉56 count | |
Case 2 | ● Cam position〈 5 CAD ● Cam position Error 〉 20 CAD ● Timing counter 〉56 count | ||
Diagnosis Time | ● Continuous (More than 0.75sec failure for every 56.25 sec. tests) | ||
MIL On Condition | ● 2 driving Cycle | ||
Resistance (Ω) | 6.7 ~ 7.7 |
IG "OFF" ＆ connect scantool.
ENG "ON" and warm -up the engine to normal operating temperature.
Monitor "CAM(B2)" status on the service data.
Are the "CMP(B2)" data displayed correctly ?
▶ 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, poorconnection, ending, corrosion, contamination, deterioration, or damage. Repair or replace asnecessary and go to "Verification of Vehicle Repair" procedure
▶ Go to "Terminal and connector inspection" procedure
Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
Has a problem been found?
▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure
▶ Go to " Power Circuit Inspection " as follow
IG "OFF" and disconnect OCV connector.
IG "ON" ＆ ENG "OFF".
Measure voltage between terminal 1 of OCV harness connector and chassis ground.
Specification : B+
Is the measured voltage within specification ?
▶ Go to " Control Circuit Inspection " procedure.
▶ Check that Fuse between Main Relay and OCV is open.
▶ Check open between main relay and OCV.
▶ Check short to ground between Main Relay and OCV.
▶ Repair or replace as necessay go to "Verification of Vehicle Repair " procedure.
IG "OFF" and disconnect OCV connector.
IG "ON" ＆ ENG "OFF".
Measure voltage between terminal 2 of OCV harness connector and chassis ground.
Specification : Approx. below 1V
Is the measured voltage within specification ?
▶ Go to "System Inspection" procedure.
▶ Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.
Visual Inspection
Check oil level is O.K.
Check oil is contaminated.
Check that any oil leakage is occurred around CVVT system.
Has a problem been found ?
▶ Repair or replace as necessary and then, go to " Verification of Vehicle Repair" procedure.
▶ Go to "Component Inspection" procedure
OCV Inspection
IG "OFF" ＆ Disconnect OCV connector.
Measure resistance between terminal 1 and 2 of OCV connector (Component Side)
Resistance (Ω) | 6.7 ~ 7.7 |
Is the measured resistance within specification ?
▶ Go to "Actuation Test" as follow.
▶ 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.
Actuation Test
IG "OFF" and connect OCV connector
IG "ON" ＆ ENG "OFF"
Check that click sound can be heard when actuation operates with scantool.
Does the OCV operate corectly when actuation operates ?
▶ Substitute with a known - good PCM and check for proper operation. If the problem is corrected, replace PCM and go to "Verification of Vehicle Repair" procedure.
There is a memory reset function on scantool that can erase optional parts automatically detected and memorized by PCM.
Before or after testing PCM on the vehicle, use this function to reuse the PCM on the others.
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.
After a repair, it is essential to verify that the fault has been corrected.
Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code(DTC) which has been diagnosed.
Using a Scantool, Clear the DTCs
Operate the vehicle within conditions noted in the freeze frame data or enable conditions
Monitor that all rediness test have been verified as " Complete "
Are any DTCs present ?
▶ Go to the applicable troubleshoooting procedure.
▶ System is performing to specification at this time.
