Fault Code: 009CAC - Brake light switch defective
 

I recently had my battery replaced but I am still getting the dreaded increased battery discharge message. I cleared all my codes and decided to use Carly. After two days no message but Carly returned Fault Code: 009CAC - Brake light switch defective. Anyone familiar with this? Could this eventually trigger the battery discharge warning?

After replacing my battery a number of years ago, I got some sort of excessive draw message (battery? current? discharge? Don't remember). What I do remember though is thinking that the battery was requiring more charging current than the computer thought that it should have. I trickle charged the battery for a few hours, then let it idle for another hour. Message was still there, took it for a ride and it went away in minutes. Has not popped up again in two years. Bottom line, a new battery does not equate to a fully charged one.

Low battery voltage can lead to all kinds of strange errors. Get the battery fully charged and in sync with the computer. Clear the codes. If the battery fault is gone and the brake switch code persists, it would leave me to believe that they are distinct.

I am not sure what to do at this point. I fully charged the battery and even pulled the fuse to the comfort access but still was getting "Increased battery discharge". I even disconnected the IBS and still getting the warning. I decided to take it to my BMW indy mechanic but no luck in finding the cause. Basically I was told to ignore it. This was happening with the previous battery so he replaced it with a new one on March 1, 2019 (World SOURCE ONE).

I continue to get "Increased battery discharge!" and also "High battery drain!" I used my carly today and pulled the following 8 fault codes.

1-002DED - power management, closed-circuit protection
2-006E83 - Fault Explanation: :PT-CAN: Signal ST IND FLTR message in STAT RDC (ID 0x31C) invalid (transmitter RDC) Please feel free to FC hide (Bosch software error) / PT-CAN: Signal ST IND FLTR message in STAT RDC; ID invalid 0x31C; RDC transmitter --- (DSC: Tire Pressure Control: interface)
- - this could be because the other day I had a flat tire
3-00A559 - Fault Explanation: :KL30g f Cutoff / KL30g f shutdown / Klemme30g f shutdown / KL.30g f shutdown
4-009CAC - Fault Explanation: :Brake light switch defective
5-00D690 - Fault Explanation: :Ring break diagnosis was performed (Error ring diagnosis) / MOST: ring break / Ring break diagnosis was performed (Error ring diagnosis). / TCU: ring break diagnosis was performed (Error ring diagnosis)
6-0093AB - Fault Explanation: :Relay adhesive MPM relay
7-00A85F - Fault Explanation: :PowerOn by Kl30F shutdown
8-00604E - Fault Explanation: :Error RDC system / Error tire pressure control system
- - this could be because the other day I had a flat tire

If you decide to replace your switch, this may prove helpful.

https://www.youcanic.com/wiki/change...e-light-switch