Component Location
General Description
The CVVT (Continuously Variable Valve Timing) system is installed to the chain sprocket of the camshaft. This system controls the 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 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 over all driving conditions.
DTC Description
ECM monitors CAM phasing average rate while cam signal is normally generating.
ECM determines that a fault exists and a DTC is stored while vehicle is tip - in and out driving for 5 minutes.
ECM monitors CAM phaser error while CMP signal is normally generating and vehicle is driving in 2000 ~ 3000rpm.
If the CAM phaser does not move although ECM commands OCV duty cycle ECM determines that a faultexists and a DTC is stored.
ECM monitors OCV stuck while cam sinal is normally generating and Valve cleaning is not in progress.
If the CAM Acutal Position is too high or low and Difference between Cam Actual Positionand Desire Position is higher than 20° ECM determines that a fault exists and a DTC is stored.
DTC Detecting Condition
Item | Detecting Condition | Possible cause |
DTC Strategy | Case1, 2 | Determines if the phaser is stuck or has steady-state error
| (Case1, 2) Engine Oil
OCV stuck
CVVT stuck
(Case3, 4) Oil Pressure Loss
OCV seizure
|
Case3, 4 | Determines if oil control valve is stuck
|
Enable Conditions | Case1, 2 | CAM signal is normally generating
Vehicle is on driving (2000 ~ 3000RPM) for 5 minutes.
|
Case3, 4 | Valve cleaning not in progress
CAM signal is normally generating
|
Threshold value | Case1 | 5 CAD < Cam Actual Position < 50 CAD
Duty Cycle > 90% or Duty Cycle < 10%
|
Case2 | Cam Position error > 15 CAD (Difference between Actual Postion and Desire Position is more than 15°)
Timing Counter > 80
|
Case3 | Cam Actual Position > 50 CAD and Difference between CAM Actual Position and Desire Position > 20 CAD
|
Case4 | Cam Actual Position < 5 CAD and Difference between CAM Actual Position and Desire Position > 20 CAD
|
Diagnosis Time | Case1, 2 | Continuous (Within 5min.)
|
Case3, 4 | Continuous (Within 1min.)
|
MIL On Condition | 3 Driving Cycles
|
Specification
OCV | Specification |
Coil Resistance (?) | 9.4 ~10.4 [20?(68?)] |
Diagnostic Circuit Diagram
Signal Waveform & Data
Fig.1) Normal waveform of CKPS & IN-CMPS at idle.
Fig.2) Normal waveform of CKPS & IN-CMPS at acceleration with load.
Fig.3) Normal data of IN-CVVT at idle.
Fig.4) Normal data of IN-CVVT at acceleration with load.
Fig.5) Normal graph of IN-CVVT at acceleration with load.
This example shows a typical Crankshaft Position Sensor (CKPS) and Camshaft Position Sensor (CMPS) waveform at idle.(Fig.1) If the 17th signal of the CKPS after missing tooth is aligned with the high signal of the CMPS at idle, ECM recognizes that Synchronization between CKPS and CMPS is completed. Under acceleracting condition, the number of teeth between missing tooth and tooth aligned with edge of the CMPS high signal is decreased from idle condition.(Fig.2)