DTC Advanced Diagnostics: P0741
DTC P0741 : Torque Converter Clutch Circuit Performance or Stuck OFF
General Description
| Torque converter clutch operation | Clutch pressure control solenoid valve H | ||
| ON (100 %) | OFF (0 %) | ||
| Shift solenoid valve C | ON (12 V) | Torque converter clutch: maximum duty | Torque converter clutch: minimum duty |
| OFF (0 V) | Torque converter clutch OFF | Torque converter clutch OFF | |
The power transfer capacity of the torque converter clutch is controlled by the balance of automatic transmission fluid (ATF) supplied to and discharged from the torque converter clutch and the torque converter. When hydraulic pressure supplied to the torque converter clutch is less than the torque converter internal pressure, lock-up is OFF. When hydraulic pressure supplied to the torque converter clutch is greater than the torque converter internal pressure, lock-up is ON. As the hydraulic pressure supplied to the torque converter clutch increases, the power transfer capacity of the torque converter clutch increases. The supply of hydraulic pressure is switched by shift solenoid valve C and the lock-up shift valve. When the transmission control module (TCM) turns on shift solenoid valve C, the hydraulic pressure is supplied to the torque converter clutch. When the TCM turns off shift solenoid valve C, the hydraulic pressure is not supplied to the torque converter clutch. The balance of hydraulic pressure supplied to the torque converter clutch and the torque converter is controlled by clutch pressure control solenoid valve H and the lock-up control valve. If the difference between the target engine speed and the actual engine speed is a specified value for a specified time when the torque converter clutch is ON commanded (shift solenoid valve C is ON and clutch pressure control solenoid valve H is ON), the TCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 22 seconds or more |
| DTC Type | Two drive cycles, MIL on, shift position indicator blinks |
Enable Conditions
| Condition | Minimum | Maximum | |
|---|---|---|---|
| Engine speed [Engine Speed] | 1, 000 rpm | 6, 000 rpm | |
| 12 volt battery voltage [Battery Voltage] | 10 V | - | |
| Shift status | 1st to 10th gear | ||
| Torque converter clutch | During lock-up operation | ||
| Other | Torque converter clutch is in a stable condition for at least 2 seconds | ||
| Lock-up must not be in transition condition (not in condition while actual engine speed is converging to target engine speed) | |||
| Engine torque must be value shown in table or more depending on engine speed with accelerator pedal is pressed | |||
[ ]:HDS Parameter
| Engine speed [Engine Speed] (rpm) | 1, 000 | 1, 250 | 1, 500 | 1, 750 | 2, 000 | 3, 000 | 5, 000 | 7, 000 |
| Engine torque (N.m (kgf.m, lbf.ft)) | 42 (4.3, 31.0) | 42 (4.3, 31.0) | 50 (5.1, 36.9) | 55 (5.6, 40.6) | 59 (6.0, 43.5) | 73 (7.4, 53.8) | 98 (10.0, 72.3) | 123 (12.5, 90.7) |
Malfunction Threshold
The difference between the target engine speed and the actual engine speed exceeds the value for at least 22 seconds shown in the table which depends on the relation of the mainshaft speed sensor value and the engine torque value.
| Mainshaft speed sensor value (rpm) | |||||||||||
| 1, 000 | 1, 250 | 1, 500 | 1, 750 | 2, 000 | 2, 250 | 2, 500 | 3, 000 | 5, 000 | 7, 000 | ||
| Engine torque (N.m (kgf.m, lbf.ft)) | 0 (0, 0) | 350 | 350 | 350 | 350 | 350 | 350 | 350 | 350 | 350 | 350 |
| 35 (3.6, 25.8) | 50 | 60 | 55 | 50 | 50 | 55 | 60 | 70 | 50 | 35 | |
| 50 (5.1, 36.9) | 105 | 90 | 75 | 70 | 65 | 70 | 75 | 85 | 65 | 45 | |
| 75 (7.6, 55.3) | 205 | 160 | 120 | 100 | 90 | 95 | 100 | 100 | 85 | 65 | |
| 100 (10.2, 73.8) | 320 | 230 | 175 | 130 | 120 | 120 | 120 | 120 | 100 | 85 | |
| 125 (12.7, 92.2) | 420 | 320 | 235 | 185 | 145 | 145 | 140 | 135 | 120 | 100 | |
| 150 (15.3, 110.6) | 505 | 405 | 290 | 235 | 185 | 175 | 165 | 155 | 135 | 120 | |
| 200 (20.4, 147.5) | 695 | 565 | 430 | 340 | 280 | 250 | 225 | 190 | 170 | 155 | |
| 250 (25.5, 184.4) | 850 | 720 | 580 | 470 | 380 | 335 | 290 | 225 | 205 | 190 | |
Possible Cause
- Torque converter failure (torque converter clutch)
- Valve body assembly failure (clutch pressure control solenoid valve H stuck off, shift solenoid valve C stuck off, lock-up shift valve stuck, lock-up control valve stuck)
Confirmation Procedure
Operating Condition
- Start the engine, and warm it up to normal operating temperature (the radiator fan comes on twice).
- Test-drive the vehicle on a level road with a steady throttle at 60 mph (96 km/h) for at least 45 seconds.
- Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the TCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on, the shift position indicator blinks, and a Confirmed DTC and the freeze data are stored.
Conditions for clearing the DTC
The shift position indicator comes off by turning the vehicle to the OFF (LOCK) mode. The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool clear command.