General Description
The PCM/TCM controls the locking and unlocking of the Torque Converter Clutch ( or Damper Clutch ), to the input shaft of the transmission, by appling hydraulic pressure. The main purpose of T/C clutch control is to save fuel by decreasing the hydraulic load inside the T/C. The PCM/TCM outputs duty pulses to control the Damper Clutch Control Solenoid Valve( DCCSV ) and hydraulic pressure is applied to the DC according to the DCC duty ratio value. When the duty ratio is high, high pressure is applied and the Damper Clutch is locked. The normal operating range of the Damper Clutch Control duty ratio value is from 30%(unlocked) to 85%(locked).
DTC Description
The PCM/TCM increases the duty ratio to engage the Damper Clutch by monitoring slip rpms (difference vlaue beteween engine speed and turbine speed ). To decrease the slip of the Damper Clutch, the PCM/TCM increases the duty ratio by appling more hyraulic pressure. When slip rpm does not drop under some value with 100% duty ratio, the PCM/TCM determines that the Torque Converter Clutch is stuck OFF and sets this code.
DTC Detecting Condition
Item | Detecting Condition | Possible Cause |
DTC Strategy | Stuck "OFF"
| ? TORQUE CONVERTER(DAMPER) CLUTCH : TCC Faulty TCC or oil pressure system
Faulty TCC solenoid valve
Faulty bady control valve
Faulty PCM/TCM
|
Enable Conditions | Solenoid status Plunging into
A/T range switch D range
|
Threshold Value | Time during 100% duty>4secs
|
Diagnostic Time | 4secs
|
Fail Safe | Damper clutch abnormal system (If diagnosis code P0741 is output four times, TORQUE CONVERTER(DEMPER) CLUTCH is not controlled by PCM/TCM)
|