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P0742 Torque Converter Clutch Circuit Stuck On

AutoHex Online Help: Hyundai ACCENT(RB) 2012
Component Location
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/PCM/TCM outputs duty pulses to control the Damper Clutch Control Solenoid Valve( TCCSV ) and hydraulic pressure is applied to the DC according to the TCC 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 TCM monitors the slip RPM(the difference between engine speed and turbin speed) and raises the its duty ratio in order to operate Torque Conveter Clutch.

If the duty ratio is 0 % and TCM can't sense its slipping, the TCM determines that the torque converter clutch has been stuck and sets this DTC.

DTC Detecting Condition

Item

Detecting Condition

Possible Cause

DTC Strategy

Check torque converter clutch

? TORQUE CONVERTER(DAMPER) CLUTCH : TCC

Faulty TCC or oil pressure system

Faulty TCC solenoid valve

Faulty bady control valve

Faulty PCM/TCM

Enable Conditions

Throttle Position = 20%

Output speed = 1000rpm

TR switch D,3

ATF temperature > -10?

Threshold Value

The speed value between engine speed and input shaft's speed = 5 rpm

Diagnostic Time

3sec.

Fail Safe

The torque converter clutch is not connected