The mileage is about 162 thousand km, with 272.952 engines and 722.9 transmission Benz E300 cars. The car PTS fault lights up and the system stops working. Fault diagnosis: the customer description is abnormal when the radar display is displayed when the front or back gear is hung, and the whole system stops working for a moment, and neither of the two radar displays. According to the customer's description, the vehicle test results are consistent with the customer descriptions to prove that the system is in trouble. The possible reasons for the failure are as follows: (1) damage to the PTS control module; (2) the damage of the electric eye probe; (3) the electric eye line has a local short circuit; (4) the damage of the control module after (5); (5) the damage of the radar display before and after (6) the position of the front plate frame installation. First, connect the diagnostic instrument to detect the PTS system. When testing, it is found that the PTS system can not get in, and there is no communication with the PTS control module. Dismantle the PTS control module to measure the power supply line of the PTS control module and find no voltage, so look up WIS (as shown in Figure 1) and find that the fuse of the PTS control module is the rear SAM-f80 fuse. Then look at the post SAM-f8. The fuse is burned, then a fuse is found and the diagnostic instrument is detected. The PTS control module can be detected by the diagnostic instrument, and the fault code shows that there are 1, 2, and 3 faults in the car location system, and the fault code is "no signal change and low level". The possible cause of these failures is the three electric eye damage, or the three electric eye plugs are not in good contact. The three electric eyes can not see any problems from the appearance. Then the front bar check is removed and the wire harness plug is found to have no problem. The front bar is mounted with a diagnostic instrument to check the actual value of the front and rear bars. So you delete the fault code, sit in the car and hang in the forward shift to watch the two radar displays to show normal, call a person to move near the front bar, just start normal work, but not long before the radar display is not sound, when the normal condition reaches the limit distance will make a sound, and then the front radar display. The indicator shows abnormal. Then we put the focus on the front radar display, and then use the diagnostic instrument to activate the pre radar display, and find that the work is not unstable and the system does not work, and it is clear why the fuse of the PTS control module will burn up. Remove the front radar display, see the wiring harness is good, and measure the power supply is normal. Finally, the replacement of a front radar display, repeated testing of all the normal, the problem can be solved. Troubleshooting: before replacing the radar display. Fault summary: PTS system is a relatively simple system, because the components of the system are only a few, but the correlation between these components is very strong, and any one of the problems between the system will cause the whole system problems and stop work. When we repair, we should pay attention to details and understand its preconditions, starting with the simplest one. The most common thing we usually do in our work is that there are problems with the electric eye or the electric eye wiring harness. The abnormal work of the former radar display is relatively rare. In the maintenance process, we should be good at using the diagnostic instrument, make a correct analysis of the trouble code, eliminate the possibility quickly, and improve the efficiency of maintenance diagnosis.