Symptom: an annual 2009 FAW – Volkswagen Magotan 1.8TSI automatic transmission car, the user data to reflect the transmission shift lever to the R range position, the right side exterior mirror is not deflected to the ground.
Check Analysis: Under normal circumstances, when the transmission shift lever to the R range position, the right side exterior mirror deflection angle to be ground, in order to facilitate the driver to see the situations ground. After that communicate with users, exterior mirror deflection or normal function of two days ago, was found this morning function disappeared, and issued ldquo near the exterior mirrors when linked to reverse gear; cracking, cracking rdquo; continuous the sound of the morning just open the door key into the ignition switch will also hear ldquo; cracking, cracking rdquo; sound.
by a user’s description, the maintenance personnel of the seat has been stored in the control unit of the door mirror of the deflection function. Thus remote open the door, the key in the ignition switch, then the right door mirror heard rattling, noise stops after engaging the reverse gear, not found on the right side exterior mirrors deflect emitted sound like after slipping wear the same gear motor. By manipulation of the driver-side exterior mirrors the switching regulator is adjusted in four directions are normal.
FIG 1
service personnel deflection function of the door mirror is manually set, i.e., is newly stored (set seat End after memory, linked into reverse gear, the rear view mirror adjusted according to the location, then click the button position memory), after you hear a tone indicates that the store successfully, but examination revealed rearview mirror deflection function is still no. I analysis, since the direction of the mirror can be adjusted manually, it shows the door mirror motor gear slippage does not occur. Found mirror control circuit diagram (FIG. 1), see the right front door control unit J387 reverse signal obtained from the CAN bus T20h / 8 and T20h / 9, the motor control V150 deflection function performed work. Further, CAN bus is activated after the ignition switch is opened, J387 self-test for each actuator, if the mirror is not in the initial position, it is necessary to adjust the initial position (memory position character). When adjusting the mirror control switch exterior side rear view mirror by the driver, control commands issued by the mirror switch via CANThe right front door is transmitted to the bus control unit J387, and then control the motor operation by the mirror J387.
FIG. 2
Through the above analysis, I decided to check the operating voltage of the motor in each state, if the voltage is no problem then check the line Finally, checking the control unit, the control unit because of the possibility of damage not. When measuring the line, found that the operating voltage is not turned the ignition switch when the motor is 0.94 V, after turning the ignition switch is 6 V, then the motor emits ldquo; carbazole, carbazole rdquo; sound, but does not operate because the voltage is significantly lower operating voltage of 12 V. When the actuating drive side mirror adjustment switch, the motor operating voltage is 12 V, with the motor to work properly. Through the above examination, a control line is no problem, then why manually adjust the voltage of 12 V is it? Mirror control command is issued by the J387 ah! Then I remembered once repaired a Magotan sedan, the car trunk lid open ineffective control by a switch on the left front door, and the remote control to open properly, the ultimate cause of the malfunction is the state of the tailgate switch is always turned on, a remote command preference to control the left front door button, the remote trunk lid can be opened. As for the car’s rear-view mirror is not working properly Magotan sedan, which means that the driver side rearview mirror control switch instruction to give priority to other control instructions. Voltage is found then return to normal 12 V, so far the problem clear, the two are mirror adjustment motor operating voltage caused by faults becomes smaller unplug the motor module 2, then the voltage measurements. Motor resistance measured as 24.7 Omega; (FIG. 2), to find a new motor measured and found to vary greatly resistance, resistance to the new motor 74.9Omega; (FIG. 3). Replacement of the motor measured after the operating voltage is 12 V (FIG. 4), linked to reverse gear when:
Figure 3
Troubleshooting mirror deflection function returned to normal.
Figure 4
reviewed: fault car control unit detects the motor resistance becomes small, to prevent excessive damage to the control return current means for performing a reduction processing, the control unit isSelf-protection mode. Manually adjust command has priority, so that the forced control of the control unit regulating the operating voltage output 12 V, the motor case can be properly adjusted. Since the service personnel lack knowledge of circuits to master, you will not find the key point of the failure judgment.
(Li Xin)