P0741

DTC P1786 (P0741): Torque Converter Clutch System (Stuck Off)

DESCRIPTIONS OF MONITOR METHODS

- At start of lock-up operation, if lock-up clutch cannot be engaged even when duty ratio of torque converter clutch solenoid remains 100% for more than specified time, PCM judges that torque converter clutch is stuck OFF.

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)

- DTC P0335: Crankshaft position sensor malfunction
- DTC P1766 (P0715): Input shaft speed sensor malfunction
- DTC P1767 (P0720): Output shaft speed sensor malfunction
- DTC P1787 (P0742): Torque converter clutch system malfunction (Stuck ON)
- DTC P1778 (P0743): Torque converter clutch solenoid malfunction
- DTC P1773 (P0753): Low-reverse solenoid malfunction
- DTC P1774 (P0758): Underdrive solenoid malfunction
- DTC P1775 (P0763): Second solenoid malfunction
- DTC P1776 (P0768): Overdrive solenoid malfunction
- DTC P1777 (P0773): Reduction solenoid malfunction[ 5A/T]
- DTC P1788 (P1751): A/T control relay malfunction
Sensor (The sensor below is determined to be normal)

- Input shaft speed sensor
- Output shaft speed sensor
- Crankshaft position sensor
- Torque converter clutch solenoid
- Low-reverse solenoid
- Underdrive solenoid
- Second solenoid
- Overdrive solenoid
- Reduction solenoid[ 5A/T]
- A/T control relay

LOGIC FLOW CHARTS (Monitor Sequence)

DTC SET CONDITIONS

Check Conditions

- Solenoid status: plunging into connecting condition.
- Transmission range switch position: D.
Judgement Criteria

- Time during 100% duty: 4 seconds or more.

OBD-II DRIVE CYCLE PATTERN

Start the engine, and drive at 100 km/h (62 mph) for 10 seconds. Then stop the vehicle, and turn OFF the ignition switch. After that, restart the engine, and drive again at 100 km/h
(62 mph) for 10 seconds.

TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CODE TO BE SET ARE:)

- Malfunction of the torque converter clutch solenoid valve
- Malfunction of the input shaft speed sensor
- Malfunction of the valve body
- Damaged harness or connector
- Malfunction of the PCM
- Malfunction of the torque converter

DIAGNOSIS

Required Special Tools:

- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, read the A/T diagnostic trouble code.

(1)
CAUTION:
To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK"
(OFF) position before connecting or disconnecting scan tool MB991958.

Connect scan tool MB991958 to the data link connector.
(2)Start the engine. (Warming up engine)
(3)Set scan tool MB991958 to the data reading mode.

- Item 7: Torque Converter Clutch Solenoid Valve Duty%.
- When driving at constant speed of 60 km/h (37 mph), the display should be "70 - 99.6%" (Gear range: 3rd gear[ 4A/T], 4th gear[ 5A/T]).
- When the accelerator pedal is released [at less than 50 km/h (31 mph)], the display should be "70 - 99.6%-> 0%" (decreases gradually as the vehicle speed decreases) (Gear range: 3rd gear[ 4A/T], 4th gear[ 5A/T]).
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the solenoid valve operating properly?

YES Go to Step 3.

NO Go to Step 5.

STEP 3. Using scan tool MB991958, check data list item 10: Torque Converter Clutch Amount of Slippage.

(1)
CAUTION:
To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK"
(OFF) position before connecting or disconnecting scan tool MB991958.

Connect scan tool MB991958 to the data link connector.
(2)Start the engine. (Warming up engine)
(3)Set scan tool MB991958 to the data reading mode.

- Item 10: Torque Converter Clutch Amount of Slippage.
- Driving at a constant speed of 60 km/h (37 mph), the display should be "-10 to 10 r/min."
- If the accelerator pedal is released, the display on the scan tool changes (50 km/h (31 mph) and less).
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the clutch operating properly?

YES Go to Step 4.

NO Go to Step 5.

STEP 4. Using scan tool MB991958, read the A/T diagnostic trouble code.

(1)
CAUTION:
To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK"
(OFF) position before connecting or disconnecting scan tool MB991958.

Connect scan tool MB991958 to the data link connector.
(2)Turn the ignition switch to the "ON" position.
(3)Check for A/T diagnostic trouble code.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is DTC P1786 (P0741) set?

YES Replace the PCM. When the PCM is replaced, register the encrypted code. Encrypted Code Registration Criteria Table.

NO The procedure is complete.

STEP 5. Check the hydraulic pressure (for torque converter).

Measure the hydraulic pressure for torque converter. Check if the hydraulic pressure is within the standard value. Refer to Hydraulic Pressure Test, Hydraulic Pressure Test.

Q. Is the hydraulic pressure within the standard value?

YES Go to Step 7.
NO Go to Step 6.
STEP 6. Adjust line pressure.

Adjust line pressure. Refer to Adjustments, Line Pressure Adjustment.
Then check the symptom.

Q. Is the symptom eliminated?

YES The procedure is complete.
NO Go to Step 8.
STEP 7. Replace the PCM.

When the PCM is replaced, register the encrypted code. Encrypted Code Registration Criteria Table.

Q. Is the symptom eliminated?

YES The procedure is complete.
NO Go to Step 8.
STEP 8. Replace the valve body.

(1)Replace the valve body. Transaxle Disassembly and Assembly Transaxle [4A/T] or Transaxle [5A/T].
(2)Test drive the vehicle.
(3)Check for A/T diagnostic trouble code.

Q. Is DTC 52 set?

YES Replace the torque converter. Transaxle Disassembly and Assembly Transaxle [4A/T] or Transaxle [5A/T].

NO The procedure is complete.