Error code: exterior mirror heating or electrochromic faulty

codys21 · 11-21-2020, 09:53 AM

Long story short: I have an error number 804246 that says "permanent" and reads "Left exterior mirror: exterior mirror heating or electrochromic left faulty." Any ideas?

A little more detail. I'm purchasing a used F83 from out of the area so had it inspected by a local BMW mechanic. The dealer is taking care of the other few minor items the mechanic found but the dealer said they don't plan on fixing the mirror that's causing this error code. Any idea what exactly this is or how to fix it? The mechanic was hoping the mirror glass could just be replaced but if that doesn't fix it, he's thinking the entire mirror would have to be replaced. I've tried to do some researching but came up mostly empty handed. It does look like a new mirror assembly costs several hundred dollars, though.

I don't think this is serious enough to pass up on the car, but we haven't agreed on a price yet, either (that should come today). It would be nice if I could at least negotiate the price further due to this but it would also be nice to actually figure out what is wrong and how to fix it.

Thanks for any help!
Cody

codys21 · 02-16-2021, 05:47 PM

I bought the car!

I took the car to my local BMW dealer (to get the pass-through trunk!) and had them look at the mirror but they couldn't tell off the bat what's causing it so would need to run a diagnostic (which costs $350 which would get returned if I get whatever it is fixed). The guy (who's been super nice this whole time) did give me an estimate of ~$300 to replace the entire mirror; however, it's not entirely known that the problem is the mirror itself.

Mojoman · 02-16-2021, 06:27 PM

Congrats on the car! Unfortunately, I don't know anything about the mirrors.

N1rve · 02-17-2021, 01:38 AM

I didn’t know our mirrors are heated? I only know that they auto dim and fold. Driver side only auto dims after 2017? I think. They took out the passenger side during one of the MY.

TopJimmy · 02-17-2021, 06:44 AM

Quote:

Originally Posted by codys21

I bought the car!

I took the car to my local BMW dealer (to get the pass-through trunk!) and had them look at the mirror but they couldn't tell off the bat what's causing it so would need to run a diagnostic (which costs $350 which would get returned if I get whatever it is fixed). The guy (who's been super nice this whole time) did give me an estimate of ~$300 to replace the entire mirror; however, it's not entirely known that the problem is the mirror itself.

I have a good set of US approved side mirrors, if you want a set cheap to test with. PM if interested. Perfect condition.

codys21 · 02-17-2021, 08:18 AM

Quote:

Originally Posted by N1rve

I didn’t know our mirrors are heated? I only know that they auto dim and fold. Driver side only auto dims after 2017? I think. They took out the passenger side during one of the MY.

I'm not 100% sure they're heated, either. The code error does say "heated OR electrochromic faulty" so it could just be that the auto dim is faulty. But I do have a 2015 so if you're right about driver's side only auto dims after 2017 then I don't really know what's up. Though I do find it weird if the rearview and passenger side auto dim but not the driver's.

summilux · 02-17-2021, 08:27 AM

2018 side mirrors are definitely heated (Canadian model at least). It comes on when you turn the rear heater on.

If you want to check for something easy, the side mirrors are press fit it.You can just remove them by moving the mirror all the way to one side so that there is a gap between the mirror and cover and then using a plastic trim tool or similar thing to pop it off. Maybe there is a loose or broken wire in there. If you search youtube for people replacing side mirror covers you can see how easy removal and reattachment is.

N1rve · 02-17-2021, 10:53 AM

Quote:

Originally Posted by codys21

I'm not 100% sure they're heated, either. The code error does say "heated OR electrochromic faulty" so it could just be that the auto dim is faulty. But I do have a 2015 so if you're right about driver's side only auto dims after 2017 then I don't really know what's up. Though I do find it weird if the rearview and passenger side auto dim but not the driver's.

Oh then we solved your issue. "Electrochromic" is the auto dimming. If your driver side isn't dimming, that's the fault. You can probably just buy a used M4 mirror off Ebay, pop off the painted cover and put yours in.

Rotary1 · 02-17-2021, 02:30 PM

Quote:

Originally Posted by codys21

I'm not 100% sure they're heated, either. The code error does say "heated OR electrochromic faulty" so it could just be that the auto dim is faulty. But I do have a 2015 so if you're right about driver's side only auto dims after 2017 then I don't really know what's up. Though I do find it weird if the rearview and passenger side auto dim but not the driver's.

In the manual for my f80 2017 it says that the exterior mirrors are continually heated when the car is on.

codys21 · 02-18-2021, 08:33 AM

Quote:

Originally Posted by Rotary1

In the manual for my f80 2017 it says that the exterior mirrors are continually heated when the car is on.

My manual actually says the same thing. "Both exterior mirrors are automatically heated whenever the engine is running."

Nonetheless, the auto dim is the issue.

codys21 · 02-18-2021, 08:34 AM

Quote:

Originally Posted by N1rve

Oh then we solved your issue. "Electrochromic" is the auto dimming. If your driver side isn't dimming, that's the fault. You can probably just buy a used M4 mirror off Ebay, pop off the painted cover and put yours in.

Would it be just the glass that needs to be replaced? Or something else?

N1rve · 02-18-2021, 10:02 AM

Quote:

Originally Posted by codys21

Would it be just the glass that needs to be replaced? Or something else?

I would feel it's the housing itself. What you can do is pull the mirror and check the cable with a volt meter and see if it's getting any signal. If no signal, replacing the glass would do nothing.

amancuso · 02-18-2021, 08:02 PM

Quote:

Originally Posted by N1rve

I would feel it's the housing itself. What you can do is pull the mirror and check the cable with a volt meter and see if it's getting any signal. If no signal, replacing the glass would do nothing.

The housing does nothing. The wires pass through the mirror into the door.

codys21 · 02-18-2021, 10:17 PM

Quote:

Originally Posted by amancuso

The housing does nothing. The wires pass through the mirror into the door.

So do you have any idea/recommendation on how to fix this?

amancuso · 02-19-2021, 05:20 PM

Quote:

Originally Posted by codys21

Quote:

Originally Posted by amancuso

The housing does nothing. The wires pass through the mirror into the door.

So do you have any idea/recommendation on how to fix this?

The error could be in the wiring to the mirror or the glass itself.

11-21-2020, 09:53 AM	#1
codys21 Private First Class 60 Rep 134 Posts Drives: 2015 F83 Join Date: Nov 2020 Location: Iowa iTrader: (0)	Error code: exterior mirror heating or electrochromic faulty Long story short: I have an error number 804246 that says "permanent" and reads "Left exterior mirror: exterior mirror heating or electrochromic left faulty." Any ideas? A little more detail. I'm purchasing a used F83 from out of the area so had it inspected by a local BMW mechanic. The dealer is taking care of the other few minor items the mechanic found but the dealer said they don't plan on fixing the mirror that's causing this error code. Any idea what exactly this is or how to fix it? The mechanic was hoping the mirror glass could just be replaced but if that doesn't fix it, he's thinking the entire mirror would have to be replaced. I've tried to do some researching but came up mostly empty handed. It does look like a new mirror assembly costs several hundred dollars, though. I don't think this is serious enough to pass up on the car, but we haven't agreed on a price yet, either (that should come today). It would be nice if I could at least negotiate the price further due to this but it would also be nice to actually figure out what is wrong and how to fix it. Thanks for any help! Cody
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02-16-2021, 05:47 PM	#2
codys21 Private First Class 60 Rep 134 Posts Drives: 2015 F83 Join Date: Nov 2020 Location: Iowa iTrader: (0)	Some additional info I bought the car! I took the car to my local BMW dealer (to get the pass-through trunk!) and had them look at the mirror but they couldn't tell off the bat what's causing it so would need to run a diagnostic (which costs $350 which would get returned if I get whatever it is fixed). The guy (who's been super nice this whole time) did give me an estimate of ~$300 to replace the entire mirror; however, it's not entirely known that the problem is the mirror itself. Last edited by codys21; 02-16-2021 at 06:04 PM..
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02-16-2021, 06:27 PM	#3
Mojoman Private First Class 134 Rep 186 Posts Drives: 2017 F80 ZCP Join Date: Jun 2020 Location: Iowa iTrader: (0)	Congrats on the car! Unfortunately, I don't know anything about the mirrors.
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02-17-2021, 01:38 AM	#4
N1rve Racecar Driver 1288 Rep 1,955 Posts Drives: BMW M4 Join Date: Mar 2019 Location: Beverly Hills, California iTrader: (2) Garage List 2019 BMW M4 [9.63]	I didn’t know our mirrors are heated? I only know that they auto dim and fold. Driver side only auto dims after 2017? I think. They took out the passenger side during one of the MY.
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02-17-2021, 08:27 AM	#7
summilux Second Lieutenant 162 Rep 231 Posts Drives: F80 MG & 6MT Join Date: Jan 2011 Location: Ottawa iTrader: (0)	2018 side mirrors are definitely heated (Canadian model at least). It comes on when you turn the rear heater on. If you want to check for something easy, the side mirrors are press fit it.You can just remove them by moving the mirror all the way to one side so that there is a gap between the mirror and cover and then using a plastic trim tool or similar thing to pop it off. Maybe there is a loose or broken wire in there. If you search youtube for people replacing side mirror covers you can see how easy removal and reattachment is.
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