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DTC P264C: Variable Valve Lift Sensor Circuit Low Input
 
 
 
 
CIRCUIT OPERATION
  • A power voltage of 5 V is applied to the variable valve lift sensor from the ECM terminal VLS5.
  • The power voltage is grounded to the ECM terminal VLSE from the variable valve lift sensor.
  • The sensor signal is inputted to the ECM terminal VLS from the variable valve lift sensor output terminal.
 
 
TECHNICAL DESCRIPTION
  • The variable valve lift sensor converts valve lift amount to voltage signal, and then sends it to the ECM.
  • The ECM uses this signal to control the valve lift mount.
 
 
MONITOR EXECUTION
  • Continuous
 
 
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
  • Variable valve lift system monitor
Sensor (The sensor below is determined to be normal)
  • Not applicable
 
 
DTC SET CONDITIONS
Logic Flow Chart
Check Conditions
  • More than 2 seconds have passed since the engine starting sequence was completed.
  • Battery positive voltage is between 10 and 16.5 volts.
Judgment Criteria
  • Variable valve lift sensor output voltage is less than 0.2 volt for 2 seconds.
 
 
FAIL-SAFE AND BACKUP FUNCTION
  • The valve lift is fixed to maximum. Otherwise, deenergizes the motor.
  • V.V.T. phase angle is set to most retarded position.
 
 
OBD-II DRIVE CYCLE PATTERN
  • Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 23 .
 
 
TROUBLESHOOTING HINTS (The most likely causes for this code to be stored are: )
  • Variable valve lift sensor failed.
  • Open or shorted variable valve lift sensor circuit, harness damage, or connector damage.
  • ECM failed.
 
 
 
DIAGNOSIS
Required Special Tools:
  • MB992744: Vehicle communication interface-Lite (V.C.I.-Lite)
  • MB992745: V.C.I.-Lite main harness A
  • MB992747: V.C.I.-Lite USB cable short
  • MB992748: V.C.I.-Lite USB cable long
  • MB991958: Scan Tool (M.U.T.-III Sub Assembly)
    • MB991824: Vehicles Communication Interface (V.C.I.)
    • MB991827: M.U.T.-III USB Cable
    • MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)
STEP 1. Using scan tool (M.U.T.-III), check data list item 170: Variable Valve Lift Sensor.
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
(1) Connect scan tool (M.U.T-III). Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-III) .
(2) Start the engine and run at idle.
(3) Set scan tool (M.U.T.-III) to the data reading mode for item 170, Variable Valve Lift Sensor.
(4) Warm up the engine to normal operating temperature: 80°C to 95°C (176°F to 203°F).
  • Output voltage should be between 0.2 and 4.8 volts (depends on engine operation condition).
(5) Turn the ignition switch to the "LOCK" (OFF) position.
Is the sensor operating properly?
It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions .
Go to Step 2.
 
STEP 2. Measure the sensor supply voltage at variable valve lift sensor harness side connector.
(1) Disconnect the variable valve lift sensor connector and measure at the harness side.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal VLS5 line and ground.
  • Voltage should be between 4.9 and 5.1 volts.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the measured voltage between 4.9 and 5.1 volts?
Go to Step 5.
Go to Step 3.
 
STEP 3. Check of short to ground and open circuit in VLS5 line between variable valve lift sensor connector and ECM connector.
Is the harness wire in good condition?
Go to Step 4.
Repair the connector(s) or wiring harness. Then go to Step 9.
 
STEP 4. Using scan tool (M.U.T.-III), check data list item 170: Variable Valve Lift Sensor.
(1) Start the engine and run at idle.
(2) Set scan tool (M.U.T.-III) to the data reading mode for item 170, Variable Valve Lift Sensor.
(3) Warm up the engine to normal operating temperature: 80°C to 95°C (176°F to 203°F).
  • Output voltage should be between 0.2 and 4.8 volts (depends on engine operation condition).
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the sensor operating properly?
It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions .
Replace the ECM (Refer to Removal and Installation ). Then go to Step 9.
 
STEP 5. Check of harness damage in VLS5 line between variable valve lift sensor connector and ECM connector.
Is the harness wire in good condition?
Go to Step 6.
Repair the connector(s) or wiring harness. Then go to Step 9.
 
STEP 6. Check of short to ground, open circuit and harness damage in VLS line between variable valve lift sensor connector and ECM connector.
Is the harness wire in good condition?
Go to Step 7.
Repair the connector(s) or wiring harness. Then go to Step 9.
 
STEP 7. Using scan tool (M.U.T.-III), check data list item 170: Variable Valve Lift Sensor.
(1) Start the engine and run at idle.
(2) Set scan tool (M.U.T.-III) to the data reading mode for item 170, Variable Valve Lift Sensor.
(3) Warm up the engine to normal operating temperature: 80°C to 95°C (176°F to 203°F).
  • Output voltage should be between 0.2 and 4.8 volts (depends on engine operation condition).
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the sensor operating properly?
It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions .
Go to Step 8.
 
STEP 8. Replace the variable valve lift sensor.
(1) Replace the variable valve lift sensor.
(2) Turn the ignition switch to the "ON" position.
(3) After the DTC has been deleted, read the DTC again.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is DTC P264C stored?
Replace the ECM (Refer to Removal and Installation ). Then go to Step 9.
The inspection is complete.
 
STEP 9. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 23 .
(2) Check the diagnostic trouble code (DTC).
Is DTC P264C stored?
Retry the troubleshooting.
The inspection is complete.