P1740
DTC P1740: Malfunction of Lockup/Select Switching Solenoid ValveSOLENOID VALVE SYSTEM CIRCUIT
Refer to P0840.
DIAGNOSTIC FUNCTION
TCM detects abnormal operation of the lockup/select switching solenoid valve.
DESCRIPTIONS OF MONITOR METHODS
^ Specified amount of current is not flown to the lockup/select switching solenoid valve because of an open or short circuit.
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)
^ P0741: Abnormality in lockup function
^ P0746: Abnormality in hydraulic control system function
^ P0841: Abnormality in line pressure sensor function
Sensor (The sensor below is determined to be normal)
^ Not applicable
LOGIC FLOW CHARTS (Monitor Sequence)
DTC SET CONDITIONS
Judgment Criteria
^ Lockup/select switching solenoid valve activation command (ON voltage): 1.42 volts or less (0.2 second)
^ Lockup/select switching solenoid valve activation command (OFF voltage): more than 1.42 volts (0.2 second)
OBD-II DRIVE CYCLE PATTERN
Ignition switch : ON (start the engine and keep it for 10 seconds or more)
PROBABLE CAUSES
^ Malfunction of valve body assembly (Faulty lockup/select switching solenoid valve)
^ Damaged wiring harness and connectors
^ Malfunction of TCM
PROBABLE CAUSES
^ Malfunction of valve body assembly (Faulty lockup/select switching solenoid valve)
^ Damaged wiring harness and connectors
^ Malfunction of TCM
DIAGNOSTIC PROCEDURE
STEP 1. M.U.T.-III data list
Item 36: LU/SEL changeover SOL. output
Item 37: LU/SEL changeover SOL. monitor
OK: Check that the output and monitor do not differ greatly.
Q: Is the check result normal?
YES: Intermittent malfunction
NO: Go to Step 2.
STEP 2. Check the following connector:
^ B-08 CVT assembly connector
^ C-41 TCM connector
^ A-09 Intermediate connector
Check the terminals for a contact status problem and internal short circuit.
Q: Is the check result normal?
YES: Go to Step 3.
NO: Repair the defective connector.
STEP 3. Check for open circuit and short to ground in the wiring harness between the TCM connector and the CVT assembly connector.
Between C-41 TCM connector (terminal No. 14) and B-08 CVT assembly connector (terminal No.4)
Q: Is the check result normal?
YES: Go to Step 4.
NO: Repair the wiring harness.
STEP 4. Lockup/select switching solenoid valve single unit check
Refer to Solenoid Valve Check.
Q: Is the check result normal?
YES: Go to Step 5.
NO: Replace the valve body assembly.
STEP 5. Symptom recheck after erasing diagnosis code
Q: Is the check result normal?
YES: Intermittent malfunction
NO: Replace TCM.