P1740

DTC P1740: Malfunction of Lockup/Select Switching Solenoid Valve

SOLENOID VALVE SYSTEM CIRCUIT

Refer to P0740.

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 Testing and Inspection.

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.