I have a 2008 335i. It got water in the rear footwells, and the dealer found that the cause was sunroof drains. I had them do the repair, but declined to have them remove and dry the carpets at a cost of $2,000.00. They told me that there were electronic modules under the carpet and they needed to be checked. When I picked the car up, it had a DTC and Brake alarm. They said that it was probably due to water in one of the modules under the carpet, and that it might go away as the car dried out. It hasn’t. I do not believe that there are any modules under the carpet, but I am aware of the one in the drivers footwell, and it appears to be dry. Do you have any thoughts on clearing this alarm? Thanks for your help.
Hello Mr. Luesing, I’m sorry to hear about your issue as water intrusion can lead to a lot of issues. While I do not think that there are any control units on the floor boards under the carpet there are usually on the footwells and under/behind the dash and there are control modules under the seats and there is the yaw rate sensor on the floor of the vehicle. Also there are a lot of wires under the carpet. If water gets into the vehicle the only way to try to prevent issues is to remove the carpet and dry everything, if you do not it does lead to corrosion, especially on the wires. If water did indeed get into a control module or the yaw rate sensor (it measures rotation), chances are they either are or will fail.
The first step to solve your issues is to get a BMW scan tool and find out what the codes are. From there you’ll have to diagnose the codes. I’m sorry but there is no way to even begin to try to solve the issue without a scan tool . If you let me know where you are located I can recommend someone. It will be in all likelihood a time consuming affair. Please let me now if you have any other questions. Thank you.