The CVVT (Continuously Variable Valve Timing) system is installed to the chain sprocket of the intake camshaft. This system controls the intake camshaft to provide the optimal valve timing. The PCM controls the Oil Control Valve(OCV), based on the signals output from mass air flow, throttle position and engine coolant temperature. The CVVT controller regulates the intake camshaft angle using oil pressure through the OCV. As result, the relative position between the camshaft and the crankshaft becomes optimal, and the engine torque improves, fuel economy improves, exhaust emissions decrease under overall driving conditions.
PCM monitors timing misalignment while no active faults are present and fully warmed up engine oil at idle.
If the timing is misaligned PCM determines that a fault exists and a DTC is stored.
Item | Detecting Condition | Possible cause | |
DTC Strategy | ● Determines if CAM target is aligned correctly to crank | ● Loosened CKPS ● Timing Misalignment | |
Enable Conditions | ● No active faults ● Fully warmed up at idle | ||
Thresh old value | Case 1 | ● 1 teeth misalignment at 80 ℃(176 ℉) ＜ Oil Temperature ＜ 90 ℃(194℉) | |
Case 2 | ● 2 tooth misalignment at Lower than 80 ℃(176 ℉) or Higher than 90 ℃(194℉) | ||
Diagnosis Time | ● Continuous (Within 1min.) | ||
MIL On Condition | ● 2 driving Cycles | ||
Engine Oil Temperature | Misalignment |
80 ℃(176 ℉) ＜ Engine Oil Temperature ＜ 90 ℃(194℉) | 1 tooth |
Less than 80 ℃(176 ℉) or Higher than 90 ℃(194℉) | 2 teeth |
This example shows a typical Crankshaft Position Sensor (CKPS) and Camshaft Position Sensor (CMPS) waveform at idle. If the 17th signal of the CKPS after missing tooth is aligned with the high signal of the CMPS at idle, PCM recognizes that Synchronization between CKPS and CMPS is completed.
Check DTC Status
Connect scantool to Data Link Connector(DLC).
IG "ON".
Select "DTC" button, and then Press "DTC Status" to check DTC's information from the DTCs menu.
Read "DTC Status" parameter.
Is parameter displayed "Present fault"?
▶ Go to "System Inspection" procedure.
▶ Fault is intermittent caused by PCM memory was not cleared after repair. Erase DTC and drive the vehicle to satisfy the enable condition then, go to " System Inspection" procedure.
Check oil level is O.K.
Check for contamination of engine oil and OCV.
Has a problem been found?
▶ Repair or replace as necessary and then, go to " Verification of Vehicle Repair" procedure.
▶ Go to "Visually check CKPS and target wheel" as follows.
IG "OFF"
Visually check CKPS is loosened or target wheel is deformed or damaged.
Are normal conditions present?
▶ Go to "Check CAM PHASER with actuation test" as follows.
▶ Repair or replace as necessary and then go to"Verification of Vehicle Repair" procedure.
Connect scantool and IG "ON"
Select "CAM PHASER INTAKE BANK 1" on the Actuation Test.
Select "OIL CONTROL VALVE" on the Actuation Test.
Activates "CAM PHASER INTAKE BANK 1" by pressing "STRT(F1)" key.
Activates "OIL CONTROL VALVE" by pressing "STRT(F1)" key.
Repeat this procedure 4 or 5 times to ensure CAM PHASER and intake valve control solenoid reliability.
Has a problem been found?
▶ Substitute with a known - good CVVT or OCV and check for proper operation.
If the problem is corrected, replace CVVT or OCV and go to "Verification of Vehicle Repair" procedure.
▶ Fault is intermittent. Drive the vehicle to meet the enable condition for the DTC. and Go to "Component Inspection" procedure.
IG "OFF" and connect scantool.
ENG "ON" and Measure signal waveform at signal terminal of CMPS.
Measure signal waveform at signal terminal of CKPS.
Specification : 17th signal of the CKPS after missing tooth is aligned with the high signal of the CMPS at idle, PCM recognizes that Synchronization between CKPS and CMPS is completed.
Is the measured signal waveform O.K?
▶ Fault is intermittent. Drive the vehicle to meet the enable condition for the DTC. and Go to "Verification of Vehicle Repair" procedure.
▶ Go to "Timing Mark Inspection" procedure as follows.
IG "OFF" and check for correct timing mark alignment.
Is the timing mark correctly aligned?
▶ Fault is intermittent. Drive the vehicle to meet the enable condition for the DTC. and Go to "Verification of Vehicle Repair" procedure.
▶ Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.
After a repair, it is essential to verify that the fault has been corrected.
Connect scantool and select "DTC" button.
Press "DTC Status" button and confirm that "DTC Readiness Flag" indicates "Completed". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions
Read "DTC Status" parameter
Is parameter displayed "History(Not Present) fault"?
▶ System performing to specification at this time. Clear the DTC
▶ Go to the applicable troubleshooting procedure.
