VCDS Airbag problem: resistance too low

D

Daniele

New Member
Hi guys, I hope this is the right place to post. I ran into a problem restoring my A2 and I need some help for fix it. So I bought a 2002 1.6 FSI which has not been turned on for 4 years, battery was of course dead, some minor issued but nothing too serious, changed the essentials, put in a brand new battery and the car started without blinking an eye.

So, now come the problem i'm dealing with. When I turned on the car, I could see that the Airbag led stayed on. I connected my VCDS and made a scan, Airbag ECU (8Z0959655E) was faulty and so I was unable to connect. I bought an used ECU online, replaced the car's one, coded the "new" ECU and I'm now able to read an airbag fault error:

00589 - Airbag Igniter; Passenger Side (N131): Resistance too Low

Of course I tried to reset the error but I wasn't lucky and the error came back in a second. I searched a little on the forum but I found nothing, I did some other research on the internet and found just a few post in which people resolved the problem replacing the passenger airbag. So I gave it a try and bought an used airbag, sprayed some WD-40 on the connectors, connected it and tried to erese the error but again no luck for me. I also tried to run a scan without the airbag connected, same error. I read on Ross-Tech Wiki that the possible cause are the following:

Wiring from/to Airbag Igniter Passenger Side (N131) faulty
Airbag Igniter Passenger Side (N131) faulty

Assuming that the airbag igniter is good (I replaced the airbag and even without the airbag on the error is still there), what should my next move be?

Thank you for your time guys.
 
Firstly, some airbag errors cannot be cleared with VCDS.
I'd want to check out the airbag wiring, with no airbag, and no battery fitted, make sure the connection are good, that you have continuity, and no short circuit in the loom.
Given the risk of injury associated with airbags, please be very careful. Lastly, WD-40 is not a good contact cleaner, quite the opposite.
Do you have the electrical schematic for the A2?
Mac.
 
PlasticMac said:
Firstly, some airbag errors cannot be cleared with VCDS.
I'd want to check out the airbag wiring, with no airbag, and no battery fitted, make sure the connection are good, that you have continuity, and no short circuit in the loom.
Given the risk of injury associated with airbags, please be very careful. Lastly, WD-40 is not a good contact cleaner, quite the opposite.
Do you have the electrical schematic for the A2?
Mac.
Click to expand...
Mac, almost all airbag connectors I have seen are shorted at the connector. This is to prevent ESD spikes. When the connector is unplugged the two pins are shorted internally by a spring. So of you actually see a short between the two pins it means that the airbag module is disconnected.
 
PlasticMac said:
Firstly, some airbag errors cannot be cleared with VCDS.
I'd want to check out the airbag wiring, with no airbag, and no battery fitted, make sure the connection are good, that you have continuity, and no short circuit in the loom.
Given the risk of injury associated with airbags, please be very careful. Lastly, WD-40 is not a good contact cleaner, quite the opposite.
Do you have the electrical schematic for the A2?
Mac.
Click to expand...

Thank you for your reply @PlasticMac. About the electrical schematics, I've found something on the internet, they appear to be the original Audi documents, I'm trying to figuring out their content.

Evripidis said:
Mac, almost all airbag connectors I have seen are shorted at the connector. This is to prevent ESD spikes. When the connector is unplugged the two pins are shorted internally by a spring. So of you actually see a short between the two pins it means that the airbag module is disconnected.
Click to expand...

About the wirings, they are my main suspect at the moment. So based on what @Evripidis just wrote, if the connector are shorted internally by a spring, can I just move or remove the spring to get electricity back through the cable? Also this occured in both the connecteros (the one on the airbag and the one at the end of the wire) or just on one of them? Sorry for the dumb question, I'm trying to fix it myself but I'm not that espert, I learn by doing
 
Don't modify the connector because this would be a safety concern.

I am not sure from the error code which airbag is it, the one behind the dash or the seat?

If it is the seat then it would be easier to check if there are loose/damages wires as they are underneath the seat.
 
Evripidis said:
Don't modify the connector because this would be a safety concern.

I am not sure from the error code which airbag is it, the one behind the dash or the seat?

If it is the seat then it would be easier to check if there are loose/damages wires as they are underneath the seat.
Click to expand...
It is the one behind the dash, front passenger's side (N131)
 
Daniele said:
Thank you for your reply @PlasticMac. About the electrical schematics, I've found something on the internet, they appear to be the original Audi documents, I'm trying to figuring out their content.



About the wirings, they are my main suspect at the moment. So based on what @Evripidis just wrote, if the connector are shorted internally by a spring, can I just move or remove the spring to get electricity back through the cable? Also this occured in both the connecteros (the one on the airbag and the one at the end of the wire) or just on one of them? Sorry for the dumb question, I'm trying to fix it myself but I'm not that espert, I learn by doing
Click to expand...
You can download the schematic, and much more, from Audi Erwin. Pay for one hour, about 8 Euros.
Mac.

erWin - Login

erwin.audi.com erwin.audi.com
 
Andrew said:
Good Morning Daniele,

If you need some help understanding wiring diagrams then Ross-Tech have two short introductory videos, quite good for getting started.


Andy
Click to expand...
Thank you so much Andrew, this really helped me, I was looking at the diagram but I could not understand everything.

So, I've located the the "N131 Airbag igniter 1, front passenger's side" in the diagram and I can see that it is wired to the Airbag control unit (J234) with two wires, a white one and a grey one. Both wires have a "3-pin connector, yellow, behind airbag unit" (T3a/1 & T3a/2). So if i'm understanding, right where this pins are located, there is an open circuit that close when there is no airbag connected (I suppose this is the spring @Evripidis was talking about in the previous post) and when the circuit is closed, the airbag can not be powered, right? If everything is correct (I'm very unsure about that), opening the circuit will resolve the problem, right?
 
Daniele, the spring is integrated in the connectors. I do not think that this is the cause of your trouble. Check for the fitment of the connector and the routing of the wires. Maybe someone attempted a repair on the vicinity and cause some damage. Or something similar.
 
Evripidis said:
Daniele, the spring is integrated in the connectors. I do not think that this is the cause of your trouble. Check for the fitment of the connector and the routing of the wires. Maybe someone attempted a repair on the vicinity and cause some damage. Or something similar.
Click to expand...
Ok, many thanks, I'll check both wires and connectors as soon as possible. If you have any other recommendation, I'd gladly listen to you
 
So, a little update. Unfortunately, I still need help because I had no luck. I've checked all the connectors, they seems to be fine, tried to unplug and replug them, reset the error but it come back in a second. I also tried a resistor on the cable, as many internet posts suggest, but it didn't work. I also opened the 3-pin yellow connector behind the dash to check if there was the spring we was talking about but I found nothing, just the two wires and the plastic holding. From the scheme I've got it seems that the spring should be right there so maybe I've misunsterstood. Any more suggestion? Thanks in advance.
 
What resistor did you fit, what value I mean. They are usually around 3 Ohms,

The "spring" is is in the form of the terminals, you cannot actually make it out unless you look real close. They are self-shorting connectors, if they are not mated to another connector they short the two pins together. If you fit the resistor correctly then the error code should go out, unless the specific airbag unit by Audi used on this car will not let you remove the trouble code and it has to be done at the dealers. This is my reasoning at least and I stand to be corrected. Someone more capable with VCDS will jump in I am sure.

Evros
 
Evripidis said:
What resistor did you fit, what value I mean. They are usually around 3 Ohms,

The "spring" is is in the form of the terminals, you cannot actually make it out unless you look real close. They are self-shorting connectors, if they are not mated to another connector they short the two pins together. If you fit the resistor correctly then the error code should go out, unless the specific airbag unit by Audi used on this car will not let you remove the trouble code and it has to be done at the dealers. This is my reasoning at least and I stand to be corrected. Someone more capable with VCDS will jump in I am sure.

Evros
Click to expand...
There are air bag codes that can't be cleared with VCDS. As @Evripidis suggests, dealer level diagnostics, for compliance, type approval I'm guessing, or product liability perhaps ...
There are ebay sellers of gizmos that claim to clear them, but on another forum, results are very mixed.
Mac.
 
Are you sure about that guys? Because I've seen many videos about resetting airbags error codes with VCDS on this and other VAG cars. From what I was able to seen, many people were able to reset both fault code "00588 - Airbag Igniter; Driver Side (N95): Resistance too Low" and fault code "00589 - Airbag Igniter; Passenger Side (N131): Resistance too High" which are very similars to mine.

Today I've also been to an Audi service shop and asked them about this error. I talked to an assistant that confirmed that the error is related to the passenger airbag. He told me that they could fix this error by replacing the passenger airbag and reset the fault code, he even show me the instrctution given by his PC to do so and the serial code of the airbag which should be installed (I already bought the right one by the way). Unfortunately they have to put a new airbag (not an used one) and they are forced to order it from Audi service line but Audi no longer made A2's pieces so they are unable to order it and to fix the error.
 
Daniele said:
Are you sure about that guys? Because I've seen many videos about resetting airbags error codes with VCDS on this and other VAG cars. From what I was able to seen, many people were able to reset both fault code "00588 - Airbag Igniter; Driver Side (N95): Resistance too Low" and fault code "00589 - Airbag Igniter; Passenger Side (N131): Resistance too High" which are very similars to mine.

Today I've also been to an Audi service shop and asked them about this error. I talked to an assistant that confirmed that the error is related to the passenger airbag. He told me that they could fix this error by replacing the passenger airbag and reset the fault code, he even show me the instrctution given by his PC to do so and the serial code of the airbag which should be installed (I already bought the right one by the way). Unfortunately they have to put a new airbag (not an used one) and they are forced to order it from Audi service line but Audi no longer made A2's pieces so they are unable to order it and to fix the error.
Click to expand...
The kit used by Audi dealers is not VCDS, this is the point being made.
Some air bag warning can be cleared with VCDS. Other require a replacement air bag, and dealer level software to confirm this.
I have no idea which errors can be cleared, and which cannot. But if you cannot clear your error, despite fitting a good replacement, then that's one that can be cleared with VCDS.
We have a specialist company here called airbag man, who are independent airbag techs. Maybe a similar service is available to you?
Mac.
 
Italy is a big country, but I am currently on the shores of Lago d'Iseo. I have my VCDS laptop with me, along with enough tools to be able to remove the airbag and establish where the problem lies. Rumour has it that I know the A2's electrics fairly well.

If you are able to place your A2 under my nose, I'll gladly help. I'm here all day today, tomorrow and Friday. On Saturday, I'm vanishing into the deeper Alps again.

Cheers,

Tom
 
Sorry @timmus, I missed your message, really appreciate your help though. I apologize. I hope you enjoyed your trip, I'm a little too far from Iseo and I can't drive the car at the moment so I think it would've been impossible anyway. But can you confirm me that this error can be reset? This is my main concern right now. I've bought a fistfull of resistances so I will try to redo the trick as soon as possible, nothing I've done has worked at the moment.
 
UPDATE: I solved my problem.

First of all, I'd like to thank all of you guys for the help, schematics were very helpful and the video to learn how to read them was fundamental.

I was really hurting my head trying to solve this puzzle so I decided to do some test. I disconnected the seats' airbags and run a scan with OBD11 and got the error opposite to mine, "resistance too high". I reconnected the seats' airbags and this error was gone, but not the "resistence too low" one's referred to the passenger's airbag. Anyway I have tought that the "high" error was refferred to the terminal side of the cable link while the "low" error was refferred to the ECU side (I hope I explained myself enough clearly). I then checked the cable that connect to the ECU (the big and yellow one) and I saw a little damage in one hole, the plastic was a little broken. I saw that on the cable there are some numbers and that the damage was on the line that begins with 29 and ends with 56. I counted the holes and the damage was right in the middle of the 37th and 38th holes which, according to the schamatics, are exactly the electrical connections of the passenger airbag. I also unmonted the ECU to check if everything was allright and it definitely wasn't because there was a bent pin, the 38th. I carefully straightened it and put everything back in place, put a 4.7 ohm resistor instead of the airbag to run a test, cancelled the error with OBD11, turn the key on and everything was fine, no more airbag light on the dash. I then unplug the resistor, replug the airbag, checked once again and everything is still good. Job done.

So, a few notes from my experience, for future reference:

- The error is clearable (even with OBD11, but of course it must be fixed otherwise it won't gone away;
- I opened all the connector I could and found no springs, so I really don't know where those springs are, I even opened the old ECU I have and found nothing.
- If somebody is interested in why I bought an OBD11 instead of a VCDS: I bought an OBD11 w/ Pro Plan because I found out that my friend's VCDS is a fake one, it's sold from a website and even if they states everything works, I prefered avoiding, they are not related to Tech-Ross and I thing they are not autorized to sell it. I'd want to check the coding of the airbag ECU and recoding it if needed so VCDS-Lite was not good for me. Anyway the ECU was coded right but for reference OBD11 can code the ECU and made "adaptions" quite well.

Thank you once again to you all!
 
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