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DTC P1040: Incomplete Minimum Valve Lift Position Learning
 
 
 
 
TECHNICAL DESCRIPTION
  • The ECM monitors whether the initial learning for a minimum valve lift position is complete. If other diagnostic trouble code is stored in the ECM, the system cannot perform the initial learning for a minimum valve lift position.
  • The ECM will erase the diagnostic trouble code automatically when the system has learned the minimum valve lift position completely.
 
 
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)
  • Not applicable
Sensor (The sensor below is determined to be normal)
  • Variable valve lift sensor
  • Variable valve lift control motor
 
 
DTC SET CONDITIONS
Logic Flow Chart
Check Condition
  • Ignition switch is "ON" position.
Judgment Criteria
  • The system has not completed the initial learning for a minimum valve lift position yet.
 
 
FAIL-SAFE AND BACKUP FUNCTION
  • Deenergizes the variable valve lift control motor.
 
 
OBD-II DRIVE CYCLE PATTERN
  • None.
 
 
TROUBLESHOOTING HINTS (The most likely causes for this code to be stored are: )
  • The system has not completed the initial learning for a minimum valve lift position yet.
  • Malfunction of the variable valve lift mechanism.
 
 
 
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), read the diagnostic trouble code (DTC).
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) Turn the ignition switch to the "ON" position.
(3) Read the DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the diagnostic trouble code other than P1040 stored?
Refer to, Diagnostic Trouble Code Chart .
Go to Step 2.
 
STEP 2. Perform the initial learning for a minimum valve lift position.
(1) Initialize the learned value for the MFI engine. Refer to GROUP 00, Precautions Before Service - Initialization Procedure for Learning Value in MFI Engine .
(2) Perform idling learning for the MFI engine. Refer to GROUP 00, Precautions Before Service - Learning Procedure for Idling in MFI Engine .
(3) After the DTC has been deleted, read the DTC again.
Is DTC P1040 stored?
Go to Step 3.
The inspection is complete.
 
STEP 3. Variable valve lift mechanism check
Refer to GROUP 11A, On-vehicle Service - Variable Valve Lift Mechanism Check .
Is the check result normal?
Go to Step 4.
Repair it. Then go to Step 5.
 
STEP 4. Perform the initial learning for a minimum valve lift position.
(1) Initialize the learned value for the MFI engine. Refer to GROUP 00, Precautions Before Service - Initialization Procedure for Learning Value in MFI Engine .
(2) Perform idling learning for the MFI engine. Refer to GROUP 00, Precautions Before Service - Learning Procedure for Idling in MFI Engine .
(3) After the DTC has been deleted, read the DTC again.
Is DTC P1040 stored?
Go to Step 5.
The inspection is complete.
 
STEP 5. Using scan tool (M.U.T.-III), read the diagnostic trouble code (DTC).
(1) Turn the ignition switch to the "ON" position.
(2) After the DTC has been deleted, read the DTC again.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Is DTC P1040 stored?
Retry the troubleshooting.
The inspection is complete.