P0021

P0021

Component Location:

General Description
The CVVT (Continuously Variable Valve Timing) system is installed on the chain sprocket of the intake camshaft. This system controls the intake camshaft to provide the optimal valve timing for every driving condition. The ECM 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.

DTC Description
PCM detects CAM phasing average rate while cam signal is normally generating.
PCM determines that a fault exists and a DTC is stored while vehicle is tip - in and out driving for 5 minutes.

DTC Detecting Condition:

Signal Waveform:

Schematic Diagram:

Monitor DTC Status
1. Check DTC Status
1. Connect scantool to Data Link Connector(DLC).
2. IG "ON".
3. Select "Diagnostic Trouble Codes(DTCs)" mode, and then Press F5(INFO) to check DTC's information from the DTCs menu
4. Read "DTC Status" parameter.






5. Is parameter displayed "Present fault"?

YES
a. Go to "System Inspection" procedure.

NO
a. 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.

System Inspection
1. Visual Inspection
1. Check oil level.
2. Check OCV for contamination or leakage.
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 resistance
1. IG "OFF" and disconnect OCV connector.
2. Measure resistance between terminal 1 and 2 of OCV. (Component Side)

a. Specification :
Resistance : 6.7 - 7.7 ohms






3. Is the measured resistance within specifications ?

YES - Go to "Check CAM PHASER with actuation test" as follows.

NO - 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.

2. Check CAM PHASER with actuation test
1. connect scantool and IG "ON"
2. Select "CAM PHASER INTAKE BANK 2" on the Actuation Test
3. Select "OIL CONTROL VALVE" on the Actuation Test
4. Activate "CAM PHASER INTAKE BANK 2" by pressing "STRT(F1)" key
5. Activate "OIL CONTROL VALVE" by pressing "STRT(F1)" key
6. Repeat this procedure 4 or 5 times to ensure CAM PHASER and intake valve control solenoid reliability






7. Has a problem been found ?

YES
a. 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.

NO
a. Fault is intermittent. Drive the vehicle to meet the enable condition for the DTC. 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. Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode
2. Press F5(INFO) and confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions
3. Read "DTC Status" parameter
4. Is parameter displayed "History(Not Present) fault"?

YES - System performing to specification at this time. Clear the DTC

NO - Go to the applicable troubleshooting procedure.