120d flickering cabin lights suddenly

Stompie

Member
Hi guys,

Since i have had the car while driving usually after some throttle i would get the yellow exclimation and the needles would drop and come back in a sec. I then needed to restart the car and the yellow exclimation would be gone.

This would happen on and off but the last couple weeks happened more frequently.

This afternoon driving hom i floored under a bridge up towards my house and the needles droppes, yellow lights and exclimation ect and as i accelerated it would keep dropping the needles ect, first time it has done this.

Got home and switched the car off and on to clear the error and all was gone. As soon as i revved the car i noticed the cabin light flicker as i rev making me think its battery or alternator... Possibly regulator.

Couple weeks back i checked the volts in the hidden menu and if i recal it was around 15v while driving?

Has anyone experienced this issue or what could it be?

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Using the hidden menu, On idle i get 13.9v and reving jumps to 14ish volts.

Switch car off and its on 12.3V after about 10 minutes
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Danny2

///Member
15V volts would be overcharging.. A cars ideal charging is 13.8 to around 14.2 volts.

what is the fault code that comes up?
 

Stompie

Member
Danny@DSCmotorsport said:
15V volts would be overcharging.. A cars ideal charging is 13.8 to around 14.2 volts.

what is the fault code that comes up?
It only goed 15V when driving not idling.

Is there a way to check codes in hidden menu?

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Checked now and i have a valeo alternator

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So i unplugged the little plug on te alternator... Not sure what its for but assume it goes to regulator?

Tool a drive now with some mixed driving, AC on ect and no more cabin light flicker, errors on dash with exclamation didnt happen.

Checked the voltage while driving and it was 13.8 tot 14.1 volts and did not go up to 15v at all?

Think se is haunted or regulator starts acting up if it gets hot.

Will see if she behaves tomorrow

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Stompie

Member
Drove to work this morning and enabled the Voltage display and while driving and the volts were between 13.7 and 14 volts and did not spike once.

Would like to see if it spikes when the dash board goes all heywired with needles dropping.

Is the Valeo alternator's regulator replaceable?
 

DangerD

Member
Howsit gents

I had the exact same problem on my 05 E90 320d.

It started happening after I ventured onto a dirt road. It happened aggressively right after I left that road and for 3 more months. Thereafter, it started happening less.

After a year, it stopped happening on its own.

Dust in some sensors perhaps?? Loose connections?
 

Stompie

Member
Well i tightened all the connections in the boot on the battery, Checked the plug on the alternator and issue is currently gone again.

I suspect it might be the regulator that is starting to act up cause the issue with the cluster going all funky happens around every 2nd week, so might be spiking the voltage causing that to happen.

Last night and today it did not happen but will monitor it.
 

Stompie

Member
Hi guys, so still having issues amd guessing its alternator?


I can drive to work and in afternoon drive to my daughter school without any issue but after going in at school if and seems the car stood for like 5 min it seems the alternator heats up because as soon as i start the car and drive off i start getting the dsc, abs, tyre indicator, cluster needles dropping.

On the video i took a drive amd you can see while having the error the volts spike to 15v and actually saw it spike to 17v once

The battery i see is marked 2011, could it be battery or is this definitely the alternator giving in?

Any help would be appreciated

@Danny@DSCmotorsport

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Stompie

Member
Ok so i am really confused as to what is causing this issue and im almost positive its due to the alternator heating up or something weird.

I drove to work this morning while monitoring the Volts on the dash and it was constantly at 13.9v - 14.0v without ever spiking and heavy fluctuation and no errors occurred.

Now this error only happens in the afternoon as soon as i leave my daughters school which means the car stood for about 5 min while im in to fetch her. Before that all the way from Sandton to her school the voltage behaves and no errors.

So as soon as i then pull away i take it the alternator starts spiking the volts which causes the errors to pop up.

Yesterday after i picked her up and sitting in some heavy traffic, it even got worse, with the car wanting to cut out, wipers going on and me being unable to switch them off, All sorts of lights coming on ect.

Im scanning the car this morning with a tool to see if i can find anything that might confirm its alternator although i am positive its the alternator.

The belt tension is 100% and the belt looks fairly newish. I checked the battery yesterday, removed all wiring, cleaned posts ect and fitted back.

Sorry for the long post, just trying to get this resolved.


Found a guy "Mario Uys" from M3nace Auto Developments on facebook that has a second hand Valeo for R900 and he will also install it for R400 and scan and clear all codes? Anyone know him on here
 

Danny2

///Member
Hi bud,

If you can bring the car passed I can scan the car with the BMW tools and see if it throws up any faults.

It's possible it could be the alternator causing the issues.
 

Stompie

Member
Danny@DSCmotorsport said:
Hi bud,

If you can bring the car passed I can scan the car with the BMW tools and see if it throws up any faults.

It's possible it could be the alternator causing the issues.

Just weird how it only happens after switching the car off after a drive.

Been reading up on the BSD line on the alternator and IBS on the battery that could cause these sort of issues and that people have disconnected either to resolve issues like these? Apparently they heat up and start giving wrong info to the ECU causing the alternator to spike or drop in volts.

As a test, can one disconnect the BSD line on the alternator or disconnect the IBS connector on the battery as part of a test to see if it happens again perhaps today after my drive?

I will be scanning the car today at work, will post up any codes as well.


Ok seems my car doesnt have IBS on negative cable
 

Stompie

Member
UPDATE

Took the kar in to F & R Auto Electricians as recommended by @Danny@DSCmotorsport yesterday.

Regulator was causing all the issues which they replaced using an original France Valeo part which was quite expensive but no generics available.

The bearings were also replaced as they were worn and the car is better than ever!

The voltage on the OBC does not fluctuate at all, stays 14.2v where as previously it used to dip down to 13.3v and shoot back to 13.9v and then when the issue started it would continuously spike to 15v for a split second.

Just a very BIG ups to Danny for all his assistance, answering all my questions and guiding me and chatting on whatsapp and continuously checking for updates ect even though i didnt take the car to him as it was quicker to just have F&R remove test and fix the alternator, Really appreciate it bud!
 
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