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A Citroen new Elysee sedan with a mileage of about 110 thousand km, equipped with 16V engine and automatic transmission. User response: the automatic transmission shift and operation mode display on the vehicle dashboard are not displayed. After receiving the car, first use the diagnostic instrument PROXIA 3 to read and delete the automatic transmission computer of the vehicle. In the automatic transmission computer, no fault code related to the information of the automatic transmission gear is not read. After the fault code is deleted, the failure phenomenon still exists. The automatic transmission computer and its working line are checked, with the AL4 automatic transmission diagnosis line beam (4199T) combined with the diagnostic junction box (4109T), the working feet of the automatic transmission computer are connected in parallel, and the voltage measurement is carried out by the multimeter to detect the situation of the automatic transmission meter and its working line. The voltage value of the connector 56VNR27 foot (working pin) is 0, and the voltage of the 56VNR28 pin is 0. Measure the fuse on the fuse box of the cockpit. The F6 fuse is in normal condition. The above operation shows that the working power supply foot, the tie - tie foot and the working line of the automatic transmission computer are normal, and the failure has nothing to do with the two feet. Check the state of the regular power supply foot and its working line of the automatic transmission computer, measure the voltage value of the 56N56 foot of the connector with the multimeter (the ignition switch closes and opens two states), and the result accords with the requirement. Continue to check the status of F5, F6 fuse in the fuse box BF01, use the multimeter to measure the interruption situation, the fuse has not been fused, the occurrence of the fault is not connected with the regular power supply foot and the working line of the automatic transmission computer. A diagnostic instrument is used to read the version number of the automatic transmission computer. It is found that the automatic transmission control software itself does not have problems. The automatic transmission computer assembly is replaced and the automatic transmission is initialized. The automatic transmission test is carried out, and the fault is not excluded. Check the state of the multi-function switch and its working line, measure the voltage value of the connector's 37 feet, 31 feet, 32 feet, 33 feet, 34 feet when the ignition switch hits the M bit, and compare the measurement results with the standard values under normal conditions without finding the anomaly, and then use the resistance gear of the multimeter. The resistance between the feet of the multi function switch connector and the automatic transmission computer connector when the ignition switch is closed is measured, and the resistance between the 37 feet and A9 feet, the 37 feet and the A10 feet, the 32 feet and the 1 feet of Al, the 33 feet, and the A12 feet (when the transmission is in P, R, N, D, 3,2), the measurement results are not found to be compared with the normal values. Question. Change the multifunction switch assembly to carry out the related operation and the fault still exists, indicating that the failure is not related to the multi-function switch and its working line (the transmission computer can identify the gear in the gearshift lever based on the interruption between the various contacts of the multifunction switch and display the display phase on the computer control panel. " Shut down information. To check the state of the automatic transmission program selector and its working line, the results are as follows: when the ignition switch is opened to the M bit, the automatic transmission computer's 56NR40 foot and the 41 foot fail to receive the key trigger signal, the automatic transmission computer automatically selects the adaptive mode, and presses the S key after the computer 56NR41 foot power. The voltage of the battery is changed to 0, and the computer receives this trigger signal and selects the motion mode. When the parameters are read with the diagnostic instrument, the information can be read, but the combination dashboard can not be displayed. After the press is pressed, the voltage of the computer 56NR40 foot is changed from the battery voltage to 0, and the computer receives the trigger signal. To choose the snow mode automatically, the dashboard does not show "*", but when the parameter is measured with the diagnostic instrument, it shows in the state of the snow mode, then press the * key back to the adaptive mode; when the transmission lever is in the 2 gear, the 1 key is pressed, the computer 6NR36 foot voltage is reduced from the battery voltage to 0, and the computer selects the mandatory 1 gear according to the signal. The operation mode (through the parameter measurement of the diagnostic instrument can read this information but not on the combination dashboard), the replacement of the program selector after the general operation, the failure exists, the above operation shows that the failure is independent of the automatic transmission program selector and its line path. To check the state of the control relay, the lock driver and its working line of the transmission rod lock driver, it is not a problem to check the connection of the drive line of the gearshift lever, and the new assembly has been replaced. Then check the working foot of the relay, then check the control of the state of the foot, the result is normal, the replacement of a new transmission rod lock driver control relay assembly after the operation of the automatic transmission, the fault exists, indicating the failure of the drive control relay, the transmission lever. The lock driver and its working line have nothing to do with it. Check the state of the combined dashboard and its working line, replace the assembly of the combined dashboard assembly and do the related operation. The failure does not disappear. Then check the state of the power supply foot and the tie foot related to the block display panel on the combined dashboard, and measure the voltage of the connector 26VJN12 foot after the ignition switch is opened, and the result is the battery power. The pressure is in accordance with the requirements. The measurement of the voltage of the 26VJN20 foot of the tie foot is 0, and the resistance between the foot and the other normal working iron points is 3000 omega (normally less than 1 omega), so the state of the tie line is checked, and it is found that there is a loose state with the contact point of the body, and the automatic transmission operation is carried out after the tool is tightened, and the transmission operation is carried out. The automatic transmission gear shift and operation mode display on the dashboard of the vehicle combination can display the gear shift information correctly, and troubleshooting at this point. Maintenance summary