Lotus 2004 Eleven Service Notes page 147

Lotus Service Notes
Camshaft Timing Control (VVT)
P0011 Camshaft Position – Timing Over-Advanced or System Performance
P0012 Camshaft Position – Timing Over-Retarded
P0076 Intake Valve Control Solenoid Circuit Low
P0077 Intake Valve Control Solenoid Circuit High
Description
The Variable Valve Timing system (VVT) on the intake camshaft can vary the timing by approximately 25°. The
camshaft relative position is varied by a system of vanes mounted on the drive end of the camshaft. The VVT
oil control valve modulates a spool valve position in accordance with the drive signal duty cycle, this in turns
controls the oil pressure applied to the vanes. A 50% duty cycle applied to the valve will hold the valve current
timing by preventing oil flow from the VVT controller housing, a duty cycle less than 50% will retard the valve
timing, a duty cycle greater then 50% will advance the valve timing.
Component connections
Sensor Connector
1
2
P0011, P0012
Monitor: Continuous
Enable Criteria:
• Engine running > 30 secs
• Coolant temperature > 60°C (140°F)
Disable Criteria:
P0116, P0117, P0118 – Coolant temperature fault codes
Potential failure modes:
• Static valve timing is incorrect
• VVT camshaft actuator failure
• VVT valve stuck open / closed
P0076, P0077
Monitor: Continuous
Enable Criteria: Engine running
Disable Criteria: None
Potential failure modes:
• VVT valve open circuit
• VVT valve short to ground
• ECU output circuit failure
Notes:
The MIL will be illuminated if the faults are present for 2 consecutive trips
Page 4
P0011
P0012
P0076
P0077
Description
Battery Voltage
VVT Oil Control Valve
ECU Pin ECU Connector
- -
49 (J3) 52 Way (Right)
Section EMP
'06 M.Y. in brackets