The CVVT (Continuously Variable Valve Timing) system built on the camshaft helps the engine decrease the exhaust gas and increase engine power and fuel economy by changing the valve open/close timing of the intake camshaft continuously. The intake valve control solenoid, the main control part of the CVVT, changes the direction of the oil path through the CVVT by the duty control of the PCM and changes the open and close timing of the intake and exhaust valves.
PCM sets DTC P0077 if the PCM detects that the OCV control circuit is open or short to battery.
Item
Detecting Condition
Possible Cause
DTC Strategy
Electrical Check
Open or short to battery in control circuit
Poor connection or damaged harness
Faulty Intake Valve Control Solenoid
Enable Conditions
10V < Battery voltage < 16V
Threshold Value
Short to battery or Line break
Diagnostic Time
2 seconds
Mil On Condition
2 Driving Cycles
Oil Control Valve
Normal Parameter At 20? (68?)
Insulation Resistance
Above 50M?
Temp.(?)
Resistance(?)
0
32
6.2 ~ 7.4
60
140
8.0 ~ 9.2
10
50
6.5 ~ 7.7
70
158
8.3 ~ 9.5
20
68
6.9 ~ 7.9
80
176
8.6 ~ 9.8
30
86
7.1 ~ 8.3
90
194
8.9 ~ 10.1
40
104
7.4 ~ 8.6
100
212
9.2 ~ 10.4
122
7.7 ~ 8.9
Fig.1) Normal OCV (-) duty ratio with idle : Approx. 12~20%
Fig.2) Normal OCV (-) duty ratio with maintaining 2000RPM : Approx. 30~50%