Why Shanghai Volkswagen Lavida air bag warning lamp

Failure phenomenon: a 2010 annual Shanghai Volkswagen Lavida sedan, equipped with 1.4TSI engine, matching DSG automatic transmission, mileage 10 km. It found that when the air bag warning lamp maintenance personnel do PDI (pre-check) is the car.

Check Analysis: After examination, in addition to the airbag warning lamp, the other electrical equipment is working properly. Firstly, the fault diagnostic VAS5051 / B airbag control unit performs troubleshooting J234, J234 found stored in a fault code B10001Amdash; mdash; driver side airbag squib resistance too low (non-sporadic). Reading the data block selected vehicle function, see N95 resistor device driver’s side airbag squib is 0.9 Omega; (normal value should be 3.0 Omega;).

Generally, due to the failure code B10001 vehicle airbag in the course of internal short circuit caused by the reset ring of F138, but taking into account the possibility of a new car is the car, the airbag is not reset ring is faulty Big. So, what causes for this DTC J234 report it? In the case where the ignition switch is turned on, the resistance value of the J234 detonation means for monitoring airbag if the detected resistance value exceeds a predetermined range, J234 corresponding fault code stored in the internal memory of the fault, and to activate the security instrument panel airbag warning lamp.

data block driver side airbag squib resistance value is low means the N95, N95 indicating the likelihood of the plug and the associated line may be faulty, without excluding the faulty control unit is connected to the airbag . J234 can be detected since the resistance value is too low N95, and activates the warning lamp K75 airbag instrument panel and can accurately report the fault code, further data blocks may be measured by a normal read fault diagnostic apparatus, and therefore the preliminary determination J234 working properly.

FIG 1

If you do not consider the possibility of resetting the airbag unit and a faulty airbag control loop, failure is likely to occur in harness connector and a driver’s side airbag airbag ignition device reset on the harness connector ring. If any of the plug is not inserted in place, it willAirbag reset cause an internal short circuit ring functions plug connection piece, such that N95 J234 detected resistance is too low, then the fault code is stored and activated airbag warning lights K75. As (FIG. 1), the plug T41 (the reset ring side) between J234 and F138 and plug T2bf (detonating device side) between N95 and F138 have shown a circuit diagram of a short-circuit connection pieces, the short-circuit connection pieces on the role prevent accidental detonation of the airbag when removing airbags and airbag reset loop. When a disconnecting any plug, short-circuit connector piece automatic connection of the two terminals of the squib harness form a closed loop. If the plug is fully inserted in place, an internal short circuit due to the structural design of the plug connector will separate pieces.

I turn off the ignition switch, remove the driver side airbags, and then turn the ignition switch and connected to the fault diagnostic VAS5051 / B, read the fault code, the fault code or B10001 again, the measurement data read the resistance value of the block or N95 0.9 Omega ;, indicating that the fault point is not on the driver-side airbag and the harness. Because, if the driver-side airbag and a short circuit fault harnesses, is removed from the balloon, low fault resistance value stored in the non-J234 should be converted to occasional accidental reset ring on a balloon, while a stored meaning ldquo; driver side airbag squib resistor means too large rdquo; non occasional failure code, the measurement data in the data block is read, the resistance value of the data becomes too high N95.

Next, the ignition switch I is closed, the reset ring remove the airbag. And then a connection failure diagnostic switch on the ignition, failure to read the stored J234 found driver side airbag igniter low resistance value becomes sporadic fault code, a fault code while one of B10001B, meaning ldquo; driver side airbag squib resistance is too large rdquo ;, read data block N95 the resistance value of the data becomes too high.

Do airbag reset ring really damaged? At this time, not too early to conclusions. The circuit diagram can be seen, connected to the airbag control unit J234 plug and the reset ring is a white needle 41 plugs the combination switch T41, the plug on the one hand to a changeover switch, wiper switch power, on the other hand to the air bagElectric power reset bladder ring is attached. I removed the plug combination switch T41 is connected directly to the airbag ring reset, and read the fault code in the data block again without loading the airbag. At this time, the fault code is stored B10001B, N95 resistance value of the display data block is too high. This indicates that the problem is not an airbag in the reset ring, because when the switch is not fixed before the combination, the fault code is removed airbag B10001, the resistance value is too low data block N95. Accordingly, the author analyzes this failure is due to a combination switch installed in place due. In order to verify his point, the author will remove and reattach the combination switch in place, plug it in T41, the reset ring and the airbag and airbag replacing, clear fault code, the fault light is off, the fault code is also no longer occurs.

to identify the cause of the failure so far, due to the combination switch is not in place, resulting in a white 41-pin plug is not fully inserted into the combination switch T41, the reset ring airbag is mounted on a combination switch, when the airbag when the reset ring is fully installed in place, but which is not fully inserted plug pins T41, which also led to the side of the combination switch short connection pieces are not separated balloon restoring ring, so that the two wires are short-circuited N95, thereby causing the airbag control unit J234 detected N95 low resistance fault, the control unit determines squib resistance is too low for the driver side airbags, are then stored fault codes and activate warning lights airbag.

Troubleshooting: the combination switch installed in place, plug it T41, refitted airbag and airbag reset ring, clear fault code, the fault light is off, the test is repeated, the fault does not occur again.

reviewed: alarm for failure to exclude the airbag, the author summarizes the following experience. If the airbag control unit stores the fault code N95 resistance is too low, it is usually due to the virtual connection or harness plug is not fully inserted in place, resulting in the two lead wires of the airbag igniter shorting connection is short-circuited, and the air bag internal short reset ring N95 resistance is too low will cause a failure; if the airbag control unit stores N95 excessive resistance fault code, usually because the airbag squib two wire circuit device caused airbag reset ring more likely to cause damage to the airbag squib N95 apparatus fault resistance is too large.

(Caoshou Jun)

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