801A4C - fault code

[shaolinx]

I've been getting this strange un-deleteable fault code 801A4C SINE: Undervoltage Detected in internal voltage supply. Looking it up it says "The SINE must be replaced." In other models, this indicates that the siren battery needs to be changed.

Does anyone know if the video below is the same steps as the f80 to do a siren battery replacement?

[Junebug85]

Hey shaolinx , did you find the fix for this?

I'm getting the same code on my 2018 G30...

801A4C - SINE: Internal Supply Undervoltage

801A4A - Anti theft alarm system: tilt sensor and interior protection deactivated.

I'm guessing both these faults might be related to the siren battery needing to be replaced.

Thanks.

[shaolinx]

Originally Posted by Junebug85

Hey shaolinx , did you find the fix for this?

I'm getting the same code on my 2018 G30...

801A4C - SINE: Internal Supply Undervoltage

801A4A - Anti theft alarm system: tilt sensor and interior protection deactivated.

I'm guessing both these faults might be related to the siren battery needing to be replaced.

Thanks.

No, I still have the error codes. This isnt a big concern so I was going to wait until the next maintenance schedule and going to take it to dealer since I was not able to find much info about it for my F80.

Pls let me know if you find any other info.

[Junebug85]

Originally Posted by shaolinx

No, I still have the error codes. This isnt a big concern so I was going to wait until the next maintenance schedule and going to take it to dealer since I was not able to find much info about it for my F90.

Pls let me know if you find any other info.

The only error code I have now is the same as you

801A4C - SINE: Internal Supply Undervoltag

I did charge my battery overnight but it made no difference.

Sure thing 👍🏼

[Halfb8d]

Bruh… I'm getting this code on BimmerLink as well and it’s the only code I can’t clear. Anyone have a link to buy the siren battery or siren module? Whatever is needed. I recently replaced my battery because my car alarm kept randomly going off. Since battery change it hasn’t happened once but I’m guessing that all the false alarms caused this “SINE” to die or the “SINE” being dead along with bad battery caused the alarm to continuously go off. Can anyone shed light on this?

[Halfb8d]

Dreaded alarm is going off randomly again. Brand new battery and registered the new battery with BimmerLink but I guess that didn’t help. Starting to think it’s the alarm module now. Has to be the SINE battery or whatever because I still have that code and now Code DE8C5E:Lin sine communication error. Might have to go to the dealership as it seems like the alarm system is failing.

[shaolinx]

Originally Posted by Halfb8d

Dreaded alarm is going off randomly again. Brand new battery and registered the new battery with BimmerLink but I guess that didn’t help. Starting to think it’s the alarm module now. Has to be the SINE battery or whatever because I still have that code and now Code DE8C5E:Lin sine communication error. Might have to go to the dealership as it seems like the alarm system is failing.

Did you ever took it to the dealer? I sitll have the code...

[YASBBYM3]

Not saying they cannot be replaced, but judging from documentation or actually lack of it, it seems this just another example of BMW forcing you to replace the entire part (also referred to as H1 in BMW Docs) part 65759493759 for about $200+ instead of allowing for user serviceable parts.

[Halfb8d]

Originally Posted by shaolinx

Did you ever took it to the dealer? I sitll have the code...

No but I did order the part. My issue is definitely the siren alarm battery being dead and since you share the code I’m thinking yours is on its way out as well. Hopefully it’s not as dead as mine to where the alarm starts going off randomly. Did some research over the weekend and found the spot where the alarm is and exactly how to replace it via this random video on YouTube I luckily spotted. Get yours replaced asap because the alarm thing is no joke and causes you to have to leave your door unlocked overnight or pulling the fuse for the alarm siren.

https://youtube.com/@rickbarragan5090

I’m either doing it myself or taking it to an indie shop.they should charge to much it looks pretty easy to get to.

https://f30.bimmerpost.com/forums/at...1&d=1690103165

[Halfb8d]

Originally Posted by YASBBYM3

Not saying they cannot be replaced, but judging from documentation or actually lack of it, it seems this just another example of BMW forcing you to replace the entire part (also referred to as H1 in BMW Docs) part 65759493759 for about $200+ instead of allowing for user serviceable parts.

Got mine for 205. Pretty ridiculous but doesn’t seem to be a hard job. BMW told me that just to diagnose my car it would be $270 alone. No thanks. Glad I found this video.

[shaolinx]

Originally Posted by Halfb8d

No but I did order the part. My issue is definitely the siren alarm battery being dead and since you share the code I’m thinking yours is on its way out as well. Hopefully it’s not as dead as mine to where the alarm starts going off randomly. Did some research over the weekend and found the spot where the alarm is and exactly how to replace it via this random video on YouTube I luckily spotted. Get yours replaced asap because the alarm thing is no joke and causes you to have to leave your door unlocked overnight or pulling the fuse for the alarm siren.

https://youtube.com/@rickbarragan5090

I’m either doing it myself or taking it to an indie shop.they should charge to much it looks pretty easy to get to.

https://f30.bimmerpost.com/forums/at...1&d=1690103165

Let us know if doing that actually fixes the issue and if the alarm location for the 750i is in the same location as the f80.

[Halfb8d]

Originally Posted by shaolinx

Let us know if doing that actually fixes the issue and if the alarm location for the 750i is in the same location as the f80.

I’ll find out tomorrow and report back. Part is scheduled to be delivered already. Euro shop I went to charged me 160 to tell me what I already knew and then wanted another 2+ hours to fix. They did however confirm it’s located in that same location. Getting a new code that wasn’t there before diagnostic today for

801C60ZGM: Initialization of FlexRay was not performed or failed. They also added that if the new siren doesn’t work it could be an antenna issue? I’m almost positive the new air alarm will fix it though.

[Halfb8d]

Update: it fixed the issue. I installed it today and it was pretty easy. It was located on the opposite side as the 750i in the one video though. Was on drivers side accessible through rear wheel well towards the top. All codes are cleared for Sine and roof center. Even coded in a new alarm chime lock/unlock. So happy this is over with.

[shaolinx]

Originally Posted by Halfb8d

Update: it fixed the issue. I installed it today and it was pretty easy. It was located on the opposite side as the 750i in the one video though. Was on drivers side accessible through rear wheel well towards the top. All codes are cleared for Sine and roof center. Even coded in a new alarm chime lock/unlock. So happy this is over with.

Nice! did you try to open the old alarm to see if the battery is replaceable? I dont want to spend 200 on a bad battery

[Halfb8d]

Originally Posted by shaolinx

Nice! did you try to open the old alarm to see if the battery is replaceable? I dont want to spend 200 on a bad battery

I didn’t but still have the old alarm so I’ll check. I don’t think though. 200 was pretty ridiculous but I literally had to.

[rambalu80]

Originally Posted by Halfb8d

Got mine for 205. Pretty ridiculous but doesn’t seem to be a hard job. BMW told me that just to diagnose my car it would be $270 alone. No thanks. Glad I found this video.

I randomly did a scan on my car and have the 801A4C and CD0487 (ZGN: Synchronization process for FlexRay failed) codes, the latter is currently not existent.

Would you mind letting us know where you bought the part from? I am not seeing it for less than $225 (tax and shipping included).