Airbag Fault - Opinion Needed

B6/7 S4/RS4
#1

After putting my drivetrain back in and front end back together, I now have some airbag fault codes showing up. Could just be a coincidence that one of them decided to go during this job. I took a vcds readout before and after switching driver side and passenger front crash sensors, it appears that MIL ON warning moved from drivers side to passenger side, have a look:

http://i304.photobucket.com/albums/nn184/boomer_3_photos/Audi%20B6%20S4/vcdslogairbagspriortosensorswap.png

VS


http://i304.photobucket.com/albums/nn184/boomer_3_photos/Audi%20B6%20S4/vcdslogairbags.png

Do you think I should attack that one sensor that I switched over to passenger side? Other suggestions welcome!

#2

Did these codes only appear after you tore the front end apart? If so i would look into making sure everything s plugged in and the harness is not pinched anywhere.

#3

Those sensors are kind of a bitch. I think there are two up by the radiator and if I’m thinking of them correctly they have pretty funky releases.

Go to the front of your car and on the driver side of the radiator look down for this…

make sure the connection is good.

https://dl.dropboxusercontent.com/u/92800314/Photo%20Jun%2003%2C%206%2040%2025%20PM.jpg

#4

They are plugged in well, I have had those front two sensors unplugged and plugged back in multiple times. If you look at those readouts it shows the MIL code moving with the sensor too.

I have only had the code since having the front end apart, but i have scrupulously checked all connectors etc. I did a quick test of the pinouts on both sensors, they didn’t have the same resistance. Again, could this also be indicating some issue with that drivers side sensor that I swapped over to pass side??

#5

Try cleaning them with some electronics contact cleaner.

You know you swapped them or you think you might have? I guess if the resistance is different the return voltage would vary for each causing codes. I’m not sure how they communicate, but swapping them is worth a try if you thing they are mixed up.

#6

It was a very purposeful swap from driver side to passenger. On the first vcds readout, it showed that the drivers side had the MIL code. After switching them (ie the sensor that i think is the culprit moved to the passenger side), the “MIL ON” code moved. I haven’t had enough experience with air bag faults to know what to do next. Wondering if it is worth it for me to change that sensor.

#7

Ok, I understand

Did they have the same part number though?

Do you clear all codes each time you swap them?

I’m also not aware of these sensors survival rates, but I would try cleaning the connections really good and making sure the connector is definitely seated all the way. Clear the codes and see what happens. If they aren’t pricey then just replace if the issue persists.