[Poochie]

Originally Posted by Rk-d

Ok. Then I have a different problem.

When my warning light goes on - the tail light is not actually working. I'll walk to the back of the car and see that the light is physically not blinking ( or else it's extremely dim and not visible in the day light).

This is not just a false alarm situation - I actually have a dysfunctional tail light when the the warning chimes. Sometimes the light will start working again and the rapid blinking inside the car goes away. Or if I turn the car off and back on again - everything is back to to normal.

For other folks who have the tail light warning - are your tail lights actually working despite the warning?

That is part of the bulb check fault. When I swapped my pre-LCI incandescent lights to LCI LEDs like what you currently have, the same exact issue occurred; the turn signal would would blink then slowly dim out. After coding out the bulb check, the issue never reappeared.

I can sense that you have your doubts this is the case, so best I can tell you is take it into the dealer and have them swap the lights again. When it reoccurs, that will confirm that nothing is wrong with the actual lighting hardware. Then maybe try disabling the bulb check.

As long as the bulb check remains active, this issue will never end. If you are not comfortable coding yourself, there are vendors here that does it for a fee.

[Rk-d]

Originally Posted by Poochie

That is part of the bulb check fault. When I swapped my pre-LCI incandescent lights to LCI LEDs like what you currently have, the same exact issue occurred; the turn signal would would blink then slowly dim out. After coding out the bulb check, the issue never reappeared.

I can sense that you have your doubts this is the case, so best I can tell you is take it into the dealer and have them swap the lights again. When it reoccurs, that will confirm that nothing is wrong with the actual lighting hardware. Then maybe try disabling the bulb check.

As long as the bulb check remains active, this issue will never end. If you are not comfortable coding yourself, there are vendors here that does it for a fee.

Appreciate the info.

I actually ordered the OBDLink Cx which is arriving tomorrow.

I'm comfortable doing this myself. I only want to make sure my problem is the same as others - don't want to code this out only to find that my issue was a little different than others. Or that the warning is disabled but the taillight randomly stops working without me knowing. From what you're telling me -- this is not the case.

My hesitation, ironically, is having the dealer trying to fix something that's not fixable with R/R - the last thing I want is a wiring harness change out (or whatever) that doesn't need to happen.

[chris719]

Originally Posted by MooMooM2

I don't understand why checking off the check light would make the car go on fire lol, that makes no sense.

I just read pages and pages of that thread. ahha that was crazy. I still don't see how something like that would cause the car to burst into flames, I guess he did say it could but I don't know enough about this but also reading Chris responses it seems somewhat safe and really the only solution? Because keeping on putting new tail lights in is not a solution here and really a waste of time and money

It is in theory a possibility that something could get hot as a result of this.

For example, if the failure of the bulb check is because there is not as much current being drawn as expected, that is a sign of a connection or a component becoming higher in resistance. One of many possible mechanisms for this is a corroded connection or cold solder joint, etc. I don't think the voltages and currents involved here are enough to cause a fire, but a source of fire in electronics that do not trip a fuse or breaker is a connection or series component becoming high resistance. The power dissipated is = to I^2 * R. If you have an increasing R you will start heating up the high resistance component or connection. Current will go down, but if the component is supposed to be near 0 ohms normally and the voltage is high it can get hot. I've seen this cause a fire, but only on 120 or 240V AC connections, not the low voltages used to drive LEDs. I would be much more worried if this was a short-circuit condition, but it really does not appear to be. It seems to be the opposite from what is posted in the other thread.

I think the issue is a combination of something minor going on with the taillight assembly or wiring harness, plus the bulb check being overly sensitive. It is probably safe to disable the bulb check, but if it happens to me under warranty I will let them replace it first before I code out the bulb check. I have no doubt there is something wrong beyond just a mismatch of the check and the tails. If it was just a coding mistake, this would happen on brand new cars, but it doesn't. It happens after some amount of miles and is almost always resolved temporarily again with a new taillight. This, to me, means that something is changing over time. It might not be significant, but only BMW really knows.

[Rk-d]

Originally Posted by chris719

It is in theory a possibility that something could get hot as a result of this.

For example, if the failure of the bulb check is because there is not as much current being drawn as expected, that is a sign of a connection or a component becoming higher in resistance. One of many possible mechanisms for this is a corroded connection. I don't think the voltages and currents involved here are enough to cause a fire, but one of the major sources of fire in electronics that do not trip a fuse or breaker is a connection or component becoming high resistance. The power dissipated is = to I^2 * R. If you have an increasing R you will start heating up the high resistance component or connection. I've seen this cause a fire but on 120V AC connections, not the low voltages used to drive LEDs.

I think the issue is a combination of something minor going on with the taillight assembly or wiring harness, plus the bulb check being overly sensitive. It is probably safe to disable the bulb check, but if it happens to me under warranty I will let them replace it first before I code out the bulb check. I have no doubt there is something wrong beyond just a mismatch of the check and the tails. If it was just a coding mistake, this would happen on brand new cars, but it doesn't. It happens after some amount of miles and is almost always resolved temporarily again with a new taillight. This, to me, means that something is changing over time. It might not be significant, but only BMW really knows.

I did notice when washing the car that water channels out pretty aggressively near that light. I wonder if there is a connection there.

The fact that this problem is sporadic and age dependent does seem atypical for a pure coding issue, I agree. I do recognize that the bulb check may simply be overly sensitive for what (may?) otherwise be acceptable age related changes to resistance over time (assuming that’s a phenomenon that occurs - a question beyond my pay grade).

[Poochie]

Originally Posted by Rk-d

Appreciate the info.

I actually ordered the OBDLink Cx which is arriving tomorrow.

I'm comfortable doing this myself. I only want to make sure my problem is the same as others - don't want to code this out only to find that my issue was a little different than others. Or that the warning is disabled but the taillight randomly stops working without me knowing. From what you're telling me -- this is not the case.

My hesitation, ironically, is having the dealer trying to fix something that's not fixable with R/R - the last thing I want is a wiring harness change out (or whatever) that doesn't need to happen.

Great and trust me, this is the only solution to correct this fault. I know it's probably difficult to believe that some random dude on a forum can address this but the actual manufacture of your vehicle can't get it together to narrow it down but it is really the case. 🙃

All your coding changes is backed up by date and time and saved on iCloud, so you can always revert it back to the original settings if you felt you messed something up..

Bimmercode is so easy to use, a chimp can figure it out - it's really an amazing option that some like that is available. It's the best $25 mod I ever spent, real talk!

If you want to be adventurous, you can also add a bunch of hidden options, like the rear fog lights, front fog lights, and infinite Welcome Light timing but I guess addressing this turn signal issue should be first priority.


Rear Fog Light Mod For US Spec Cars https://f87.bimmerpost.com/forums/sh....php?t=1450178

Coding Amber Side Markers To Front Fogs https://f87.bimmerpost.com/forums/sh....php?t=1691279

https://www.bimmerpost.com/forums/sh...php?p=23962722

[DanG]

Originally Posted by Rk-d

Ok. Then I have a different problem.

When my warning light goes on - the tail light is not actually working. I'll walk to the back of the car and see that the light is physically not blinking ( or else it's extremely dim and not visible in the day light).

This is not just a false alarm situation - I actually have a dysfunctional tail light when the the warning chimes. Sometimes the light will start working again and the rapid blinking inside the car goes away. Or if I turn the car off and back on again - everything is back to to normal.

For other folks who have the tail light warning - are your tail lights actually working despite the warning?

No. Taillights don't work with the rapid blink and warning.

[Poochie]

Originally Posted by DanG

No. Taillights don't work with the rapid blink and warning.

It's all the same, I assure you nothing is wrong with the taillight hardware.

Before we keep going around in circles on this subject, let him try disabling the bulb checks and give us his feedback.

It has worked a for about dozen other members here already and I have confidence it will put this issue and it's proposed solution to rest for good.

https://www.bimmerpost.com/forums/sh...php?p=26474708

https://www.bimmerpost.com/forums/sh...php?p=26482549

https://www.bimmerpost.com/forums/sh...php?p=26465351

[Maynard]

I suspect that a lot of the 'set your car on fire' fear comes from the original F22 issues. With those, there was an inadequate ground bus that would literally melt on some cars. I think somebody posted pics on the 2'er boards, I know I've seen them someplace. I really doubt it would set the car on fire, but I wouldn't want to chance it. And while I haven't devoted much time to that old thread, I did get a kick out of how enthusiastically insulting some of the other posters were; thanks for once again sharing this info.

[chris719]

Originally Posted by Maynard

I suspect that a lot of the 'set your car on fire' fear comes from the original F22 issues. With those, there was an inadequate ground bus that would literally melt on some cars. I think somebody posted pics on the 2'er boards, I know I've seen them someplace. I really doubt it would set the car on fire, but I wouldn't want to chance it. And while I haven't devoted much time to that old thread, I did get a kick out of how enthusiastically insulting some of the other posters were; thanks for once again sharing this info.

If I coded it off, I'd periodically inspect the connector if possible. Probably low risk, but you never know.

[Rk-d]

Pulled my tail light to look at it. There isn't a hint of corrosion on the light (which I wouldn't expect since it's new) or with the plug itself.

I got the bimmercode app and this is what it shows. I'm so tempted just to activate it, but I'm going to let the dealer give the car another once over (they'll already have the car to adjust my coilovers and realign anyway). Failing that, I will code it out. I've already talked to them about it.

[gmhl10]

Originally Posted by gopropham

I told them the exact same thing. There is absolutely no reason why that car needed to come off the lot. They said "it's routine for us to test out everything after we work on cars".

It's all bullshit of course.

That typically is the case. I used to be a BMW technician. We're always instructed to drive the car for a minute or two even for routine maintenance before bringing the car in to the stall. You know that paper with the "free inspection" that the dealer gives you? Driving it is part of that inspection because some things are difficult to see by just looking or can be missed, but can become perceptible while driving such as car not driving straight, odd ticking noises, etc... Driving it afterwards typically occurs as a check to make sure the job was done properly. You won't believe the stories I've heard even for routine stuff. Like the tech forgot to tighten the drain plug or the tech forgot to torque the wheel lug bolts after the tire rotation.

However, the real reason why they do it though is because all technicians are instructed to. If you don't, you get fired. Even if you don't get fired, majority of American dealerships are flat rate pay so you'll be super poor if you don't try to find issues to upsell. Upselling is how most service departments make their money. If you find an issue, the tech reports it to the advisor and the advisor will try to upsell you on stuff. With upselling, they can charge you the full amount and the dealer and tech get paid the full amount. With warranty work, if I remember correctly (it's been over a decade since), I believe it was around 60% or 70%. So, if a job is quoted to take 1 hour. BMW warranty will pay you only 0.6 (or 0.7) hours for the job. If it's out of warranty, you get paid for the full hour. If the issue is real bad and not covered by warranty, the dealer will try to sell you a new car and the service advisor gets a kick back if a car is sold.

Regardless of the reason why they drive the car, that really sucks to hear about your car. I'm sorry that happened.

[Poochie]

Originally Posted by Rk-d

Ok. Then I have a different problem.

When my warning light goes on - the tail light is not actually working. I'll walk to the back of the car and see that the light is physically not blinking ( or else it's extremely dim and not visible in the day light).

This is not just a false alarm situation - I actually have a dysfunctional tail light when the the warning chimes. Sometimes the light will start working again and the rapid blinking inside the car goes away. Or if I turn the car off and back on again - everything is back to to normal.

Originally Posted by Rk-d

I got the bimmercode app and this is what it shows. I'm so tempted just to activate it

There's the specific reason your signal light is dimming/flickering. The REM (rear light computer) mapping is controlled via lines of code and is apparently set to incandescent bulbs instead of LEDs on your vehicle.. SMHing..🤦

How the turn signal light flash rate is generated by a method called "Pulse-width modulation" or PWM, which turns a digital into an analog signal by changing the timing of how long the lights stays on and off.

The term "duty cycle" is used to describe the percentage or ratio of how long it stays on compared to when it turns off i.e. flashes.

BMW coded mapped duty cycle for LED and incandescent differently because incandescent bulbs naturally fades in and out but LEDs turns on/off instantly.

So say for instance the duty cycle for an incandescent bulb is set to .8, the LED duty cycle would be .2 seconds in order to smooth out each lighting operation and not appear to flicker/dim out as it does.

By correcting the coding and informing the vehicle that LEDs are installed and not incandescent bulbs, you are telling the REM that the turn signal light needs to flash for .2, instead of .8, thus, not appear to "flicker/dimming" down as you reported that it currently does.

I'm not going to nerd it up any further other than to confirm with certainty that I'm a kachillion times sure this is cause of your rapid-flashing turn signal issue and correcting the coding mapping in the REM is only true solution.

A little FYI, the US department of transportation regulates the "duty cycle" operation of the turn signal function. The DOT actually dictates exactly how turn signals on vehicles that are on the public street flashes and at what pace. That's why we can't have "Euro" - style flashing signal lights (three rapid blinks in succession) over here.

.

[golf4501]

Originally Posted by Rk-d

I did notice when washing the car that water channels out pretty aggressively near that light. I wonder if there is a connection there.

The fact that this problem is sporadic and age dependent does seem atypical for a pure coding issue, I agree. I do recognize that the bulb check may simply be overly sensitive for what (may?) otherwise be acceptable age related changes to resistance over time (assuming that’s a phenomenon that occurs - a question beyond my pay grade).

I got the fault twice both after heavy rains and a over a 4 month period. Dealer ended up replacing the entirely assembly. That was only a month ago, but I haven't seen an issue since.

[MaDoose]

I had the same issue, in both rear lights. First one side, they fixed it under warranty and then the other side had the same issue a few weeks later. Again, fixed under warranty. It hasn't happened again.

[pablom2c]

Well it looks like I jinxed myself haha… after about a year of the coding fix working, yesterday I noticed my rear left indicator was not working (did not get dash warning of course due to coding). It has been raining a lot lately over here, but there doesn't seem to be water inside the tail light. Maybe the humidity has something to do with it? The indicator looks like it was working but very very dim, in day light you can't see it but at night it is very faint you can see it up close. I saw a post that said to tap the tail light and I did a few times and then the indicator started working again normally. Is this a different fault to the coding fix? Should I check the wires or get a replacement headlight? Mine is a 2020 M2C. Are all the headlights that BMW replaces for free the same part number? There is no new updated version? Maybe there is more than one type of fault with these tail lights?

[Rk-d]

That's a bummer to hear.

My car is in the shop now getting the REM module replaced, which was BMW's next suggestion.

[Poochie]

Originally Posted by Rk-d

That's a bummer to hear.

My car is in the shop now getting the REM module replaced, which was BMW's next suggestion.

Hmm.. What a waste.. They should try replacing the engine also, you never know if it might be connected.. 😗

[Poochie]

Originally Posted by pablom2c

Well it looks like I jinxed myself haha… after about a year of the coding fix working, yesterday I noticed my rear left indicator was not working (did not get dash warning of course due to coding). It has been raining a lot lately over here, but there doesn't seem to be water inside the tail light. Maybe the humidity has something to do with it? The indicator looks like it was working but very very dim, in day light you can't see it but at night it is very faint you can see it up close. I saw a post that said to tap the tail light and I did a few times and then the indicator started working again normally. Is this a different fault to the coding fix? Should I check the wires or get a replacement headlight? Mine is a 2020 M2C. Are all the headlights that BMW replaces for free the same part number? There is no new updated version? Maybe there is more than one type of fault with these tail lights?

How and what did you change in the with coding?

That sounds like a programming issue, go back to "Expert Mode" under REM and change these four parameters to "active."

The reason your light flickers when the turn signal is illuminated is because the frequency of PWM (Pulse Width Modulation) is too slow. This change will eliminate that and give you working LED signals.

[Rk-d]

Originally Posted by Poochie

Hmm.. What a waste.. They should try replacing the engine also, you never know if it might be connected.. 😗

Snark aside, we'll see what happens.

If it fails, then there is really nothing practical left to change and I'll code it out.

[Rk-d]

Originally Posted by Poochie

How and what did you change in the with coding?

That sounds like a programming issue, go back to "Expert Mode" under REM and change these four parameters to "active."

The reason your light flickers when the turn signal is illuminated is because the frequency of PWM (Pulse Width Modulation) is too slow. This change will eliminate that and give you working LED signals.

Honest question - Not questioning the solution, but why would this spontaneously become an issue one year later with no other variable changes other than age (and possibly weather)?

[Poochie]

Originally Posted by Rk-d

Snark aside, we'll see what happens.

If it fails, then there is really nothing practical left to change and I'll code it out.

Sorry, no snark at all bro, I just find it humorous in the fact that the dealer is clueless and their solution is just to replace everything under the roof, unnecessarily racking up a bill to BMW AG. I guess that's one way to find fix an issue.

And I've seen this before, I'm sorry to say, replacing the REM not going to help:

https://www.bimmerpost.com/forums/sh...php?p=26564064

As far as why the other member you cited is still having an issue, I don't I know; maybe he missed some steps in the coding parameters necessary or did something wrong and since the subject came back up, he decided to check the back of his car and now realized that there is still an issue.

I get conflicting info from folks here all the time, I just go by whatever they claim but one thing I'm positive about is nothing's mechanically wrong with all these taillights.

You can lead a horse to water but you can't make him properly code his taillights, so I'm going to bow out on this subject before folks here feel I'm becoming contentious, as it was merely just some friendly advice since the subject kept coming up.

I sincerely hope you guys find a solution to this issue.

[Rk-d]

Originally Posted by Poochie

Sorry, no snark at all bro, I just find it humorous in the fact that the dealer is clueless and their solution is just to replace everything under the roof, unnecessarily racking up a bill to BMW AG. I guess that's one way to find fix an issue.

And I've seen this before, I'm sorry to say, replacing the REM not going to help:

https://www.bimmerpost.com/forums/sh...php?p=26564064

As far as why the other member you cited is still having an issue, I don't I know; maybe he missed some steps in the coding parameters necessary or did something wrong and since the subject came back up, he decided to check the back of his car and now realized that there is still an issue.

I get conflicting info from folks here all the time, I just go by whatever they claim but one thing I'm positive about is nothing's mechanically wrong with all these taillights.

You can lead a horse to water but you can't make him properly code his taillights, so I'm going to bow out on this subject before folks here feel I'm becoming contentious, as it was merely just some friendly advice since the subject kept coming up.

I sincerely hope you guys find a solution to this issue.

No worries man - I actually don't have a lot faith that the REM module will fix it. The dealer is trying in good faith to fix it, which I do appreciate.

I want to go through a couple of tiers of warranty before attempting coding - maybe that's more principle than anything else. But yes - quite likely a complete waste of time and if this doesn't work out, I'll need to go the coding route.

Stick around - I have a feeling I'm (we) are going to need your expertise if this doesn't work out.