Automotive Sensors: automatic transmission torque converter failure Driving jitter

For vehicles equipped with automatic transmissions , the lock-up clutch failure on the vehicle will have a huge impact . The lock-up clutch of the common faults are: lock-up clutch does not engage , can not be separated , poor bonding and slippage . Its symptoms varied, so grasp it works , characteristics and failure analysis method is very important. Maintenance personnel have been to a 1996 Ford Windstar models cars. When the vehicle is in the middle and high speed vehicles jitter , feels like engine shake and commit the same seat . According to the car speakers this fault has been repaired in several other repair shop , replacement parts on the engine a lot , but the symptoms point is not improvedFirst, the road test , the vehicle 40-80km / h between the irregularly appear jitter. First testing the engine , but no failure. At this time considerations may be caused by other factors . Then connect the computer to read the data stream detector , found that when the lock-up clutch (tcc) bonding , especially when connected to Taiwan to 40 % -60 % of the time , the vehicle will appear jitter. Thereby determine the fault is caused by a bad combination tcc . But bad turn, end table which part is causing it ? Fault may lie electronically controlled , hydraulic and mechanical systems which part . Of course, there are some special circumstances, such as when the throttle is closed, apply the brakes , acceleration or deceleration , shift , oil temperature below 60 ℃ Rotary temperature is too high and gear in the following block 3 , etc., because these time lock the clutch is engaged .Lockup clutch engagement and disengagement by a computer (pcm) via lock-up clutch (tcc) between solenoid controlled . Computer according to the throttle position sensor , speed sensor , a turbine axis sensor , gear, shift time and the brake switch signal is analyzed to provide tcc solenoid duty cycle signal , changing the tcc solenoid valve opening degree , thereby controlling operation of the clutch . For the tcc 's work, the computer is the engine speed and the turbine shaft ( input shaft ) to monitor the speed difference . When the lock-up clutch does not operate , the engine speed should be greater than the turbine shaft speed 200-300r/min; the lockup clutch engagement process, the speed difference between the two should be gradually reduced ; when the lockup clutch is fully engaged , the two speed difference should be essentially zero . Therefore, by observing the engine speed and the turbine speed ( input shaft speed ) to determine the difference between the clutch state and the good or bad . In determining the number of lock-up clutch is not engaged or when a fault can not be separated , can be connected to the transmission detector (a kind of the solenoid valve can control the working detection tool ) , disconnect the computer control of the transmission , clutch control solenoid valve artificially work , in order to determine the control part of the fault , or to perform part of the fault . If artificially controlled clutch solenoid valve work the problem persists , indicating that the electronic control part is no problem. If the fault lies in the electric control part , you should first check the influence of the work tcc signals provided by each Camshaft Position Sensor is normal, then check whether pcm signal at each Engine Coolant Temperature Sensor to work properly , the final check wire connections are good On the hydraulic part of the fault can be determined by measuring the hydraulic pressure . So this car gearbox oil pressure test carried out . Road test , jitter occurs when engaging in tcc and found no oil pressure fluctuations and anomalies. To further determine if this part is faulty hydraulic transmission , fold down the valve and install test template , using compressed air to be tested. The results show the various hydraulic valves and valve body tcc oil works well , the hydraulic part of the fault can be basically ruled out the possibility .As for the mechanical part , unable to disassemble , so only through the exclusion of other aspects of the failure to determine. Through the above aspects of the testing and analysis, maintenance personnel may only determine the fault lies in the mechanical part , i.e., the torque converter lock-up clutch .Here to remind the majority of maintenance personnel , inability to disassemble the torque converter , so it should be noted that the transmission torque converter maintenance cleaning problems and prevent foreign matter from entering and damaging the torque converter lock-up clutch . For oil drain plug torque converter , when found oil has changed , it should open the drain plug , use new oil repeatedly washed ; no drain plug for the torque converter , you can use high-pressure air inversion cleaning method .