Brake , ABS and DSC lights intermittently turns on while driving

[seank]

Originally Posted by GMSZ4M

Hi Guys. I drive a 2006 Z4M and have the same problem.

Here are my voltage test results. With Engine off, the battery is measuring at 12.5V. With the car on it's shows a reading of 14.2 at idle and jumps to 15.5 (max) if rev-ed up to 3K. I believe this to be within normal limits. Not sure what to do next to figure out if it's the battery or the alternator.

Also, am thinking of getting this, if the alternator is the issue, unless you can suggest something else.

You are going to install an autozone alternator on your z4m?

[StickMon]

Originally Posted by seank

You are going to install an autozone alternator on your z4m?

That's an interesting question.
At first blush, I was going to jump in here and say Nooooo! Don't do it!
I put a lot of AutoZone parts on my Suburban, many of which are very substandard, and I regret later. Sometimes it's good enough.

Here's the tricky bit:
Is there a difference between this and this, except the obvious double price?
Serious question. Hmmm.

$495.26 from Tischer. Also rebuilt.
Without knowing the reputations of the rebuilders, this is a total crap-shoot.

[GMSZ4M]

Originally Posted by seank

You are going to install an autozone alternator on your z4m?

Originally Posted by StickMon

That's an interesting question.
At first blush, I was going to jump in here and say Nooooo! Don't do it!
I put a lot of AutoZone parts on my Suburban, many of which are very substandard, and I regret later. Sometimes it's good enough.

Here's the tricky bit:
Is there a difference between this and this, except the obvious double price?
Serious question. Hmmm.

$495.26 from Tischer. Also rebuilt.
Without knowing the reputations of the rebuilders, this is a total crap-shoot.

It came with a lifetime guarantee so figured it couldn't be that bad. A little research showed I couldn't be further away from the truth, and these fail consistently every year or two.

Anyway, since I'm dealing with overcharging and voltage increase, seems like the voltage regulator has gone bad. So the new plan is to replace the voltage regulator with an OEM, and I should be good. Should cost in the neighborhood of $130

EDIT: BMW Parts Pro has informed me that BMW no longer sells the voltage regulator separately, which is BS. Any recommendations to buy OEM Voltage Regulator?

Edit 2:


Update to anyone who may find themselves in this same situation.

Found out my original BMW Alternator is Valeo TG15C098.

BMW would not see the part by itself. While searching I somehow landed on a Valeo supplier called American Engines Co based out of NY. They also have a eBay store and ship internationally.

You can pick up OEM Alternator or Voltage regulator with them for half the price BMW sells it at. Same stuff just not branded BMW. I ended up picking this up. Cost $68 + $8 USPS Priority Shipping.

They also said if this didn't work and I needed to pick up the alternator, they would refund the price of the voltage regulator. Spoke to a super helpful guy named Ben. Call them at +1-920-543-6446 if you have any questions.

[GMSZ4M]

Got the part and installed it. This video was super helpful.

Taking the alternator out was pretty straightforward, replacing the voltage regulator took all of 5 minutes. However, putting it back gave me quite the trouble - just wouldn't align.

Anyway, all is done and I took the voltage reading. Battery read at 12.5 and Alternator read at 14.37V +/- 0.02. No spikes even when revved to 4K.

Hopefully that solves it. Will know for sure when I take it out for a spin.

Total cost out of pocket $75.

[StickMon]

Wow. Thanks for the info.
I don't think there's anything else in an alternator that's prone to failure except the voltage regulator, but I never knew you could buy one separately.
Then again, I suppose the rebuilders must get them from somewhere.

I'll bookmark this for the inevitable day when mine goes out.

[ZStig]

whats funny is I have my old alternator sitting in the garage, wish I saw this before shelling out $550 for a remanufactured OEM one. glad I didnt' return it for the core charge, I'll keep it as a spare

where did you source your regulator?

[StickMon]

Originally Posted by StickMon

... I'll bookmark this for the inevitable day when mine goes out.

OK, that was stupid.
I should have bought a regulator for the inevitable day when mine goes out, not just bookmarked it.

Here's what I learned trying to drive to work this morning:
1) My car's not very good at telling me that the alternator failed. It was idling funny, switching abruptly between 870 and 700 rpm, but fine otherwise.
Was at least 1/2 hour later that I caught the red batt indicator flash on and off once on the dash.
2) An on-board voltmeter is a good thing to have. I was running DashCommand to see if fuel trims or O2 voltages changed with the intermittent idle.
When I saw the batt indicator flash, switched over to the screen with volts, and I was at 11.7. When I revved the engine, it dropped to 11.6.
Cut all non-essential power!! Abort mission!! Return to base!!
Down to 10.9 by the time I got home. I can't believe it was still running.

Here's what I learned while fixing it:
1) The bottom of the air filter box is held on with plastic pins through big grommets. The plastic pins don't want to come out. Easier to stretch the grommets over them. I things that's how it's supposed to work.
2) No one stocks rebuilt alternators, not even the major chains or a local dealer. Turns out this was a good thing. Took it to a local rebuilder that does nice work. $200 and 4 hour turnaround. Could have been worse.
3) Getting the thing in and out is more of a PITA than it needs to be. The bottom bracket straddles the bracket on the block too tightly. Filed the alternator bracket before putting it back in to open it up a little, but it was still a pain to get the bolts holes lined up.
4) I need new idlers. Tensioner one is really floppy. Oh, well. It was on my list anyways. Now it's gone to the top.

[Kream]

Before my alternator completely died I was watching my voltage via Torque Pro and saw my voltage ranging from 10.5-18.3. Thank goodness it didn't fry anything.

[just2talented]

Is this what you guys saw?

[StickMon]

I got one of those with a limp mode a few weeks ago while sitting at a light.
OK after shutting off and restarting. (CTRL-ALT-DEL)
DIS said "idle speed plausibility - fault no longer present".

I was taking my Son to school and we were running late.
I think the "critical moment detector" went off.

[just2talented]

I took it to my mechanic, he thought battery. I took my battery out and took it to sears to get it checked. Its fine they said. Im back at the mechanic now to see if anything code was stored.

This problem is definetly either the battery, regulator or alternator right?

[mbanshchikov]

great! I just got those lights The car was sitting for about a week with a battery tender while I was on vacation and the first day I drive it, the lights pop up. I replaced the battery about 2 months ago. The funny thing is my car only has 12.5k miles on it...

[mbanshchikov]

Originally Posted by just2talented

Is this what you guys saw?

thats what I have, but the "brake is yellow" I'm assuming you have the parking brake engaged

[sixspeed]

Originally Posted by boboleto

Anybody else experience this problem with their car?

While driving and around 2k and above rpm the all three lights (brake, ABS and DSC) will come on for a second or two and go back off, at the same time the radio and display screen shuts off and tuns back on again. The same thing will happen with the car stationary and just by revving the engine at around 2k to 3k rpm. There is also a lost of engine power whenever the lights come on.

Does anybody has an idea of what might be causing these glitches?

Bumping this thread as I've just had the exact same symptoms crop up on my Z whilst over in Germany last week.

I've got some of it on film during the drive back. Is this the same kind of issue?

My car cranks fine (battery is only about 9 months old?), so not suspecting the battery in this case. Having just read this, I'm going to give the car a check later with a multimeter for alternator issues (high voltage).

Two additional symptoms that lead me to think its the same here:

1. It only appeared to happen when moving. I thought this was to do with a loose earth though initially (and thus not being moved/jiggled around when the car was stationary). I hadn't considered it could be RPM related though.

2. Not long after this started happening, I noticed a small puddle of water that had leaked from the battery. I initially put this down to G-forces from being on track, but in hindsight the car has been on track with this battery before and I haven't previously seen this. I presume water leaking from a battery is symptomatic of being overcharged though?

[sixspeed]

Confirmed it was the voltage regulator today. Use the Torque app and my Bluetooth OBDII adapter to datalog the voltage detected. Low of 12.2V, high of 18.5V!

Amazed things don't sizzle with this kind of excess voltage going through them. Either way, car in on Monday. New regulator on order

[mbanshchikov]

hey just2talented, I tried to pm you but I dont think the message is getting through. Can you shoot me a text 978 602 0866

[sixspeed]

Just to update - had the Voltage Regulator fitted and the car is fine now.

just2talented, does your problem look the same as the video I posted?

[pokeybritches]

I just had this issue resurface. The first time I replaced the battery and positive cabling. This time, it was a little more tricky.

I don't believe it was the blower programming. I'm 90% sure it's the alternator. The issue has disappeared for now, and replacing the alternator would be a pain with the supercharger on the car.

The weird thing is the programming got screwed up, and the car thought it was an automatic. When I pulled off the road and tried to start, it wouldn't even turn over. I got a tow and replaced the battery myself. No change. My tech started digging into the coding, and found something like "shift selector not found", along with a world of low voltage codes.

[yousefnjr]

Spring has come, and old threads have new life once again

Recently been having the same symptoms described in this thread (lights flash on while driving for a second, high voltage codes, rough idle, etc). Replaced the battery (5 years old anyway...) but it's still acting up. Thought it was a loose cable at first, re-snugged... No change. Fairly certain it's the alternator/ voltage reg at this point.

Anybody have a good source for the regulator? No longer available in the link above anymore

Edit - Doing some digging... if alternator is TG15C098, the regulator for that is 593873? Found somebody selling on eBay for $40, lists as compatible with Z's (a a C-Class...). Gonna take the gamble to try and save a few hundred bucks.

Link HERE

[Finnegan]

Originally Posted by yousefnjr

Spring has come, and old threads have new life once again

Recently been having the same symptoms described in this thread (lights flash on while driving for a second, high voltage codes, rough idle, etc). Replaced the battery (5 years old anyway...) but it's still acting up. Thought it was a loose cable at first, re-snugged... No change. Fairly certain it's the alternator/ voltage reg at this point.

Anybody have a good source for the regulator? No longer available in the link above anymore

Edit - Doing some digging... if alternator is TG15C098, the regulator for that is 593873? Found somebody selling on eBay for $40, lists as compatible with Z's (a a C-Class...). Gonna take the gamble to try and save a few hundred bucks.

Link HERE

Keep us updated. You're on the right track, and if this turned out to be more cost-effective and works .

[Clearancediver]

This is on eBay.... Check compatibility listing to make sure it matches your alternator.

Input the info in the pic to pull up the listing. Can't get a url when using my smartphone app.

I bought one similar myself.

[yousefnjr]

Part came in today, just installed. Great success so far, but need more time to tell if things are really fixed. The symptoms were intermittent. Pics:

New regulator:



Alternator:


Under the cover, old regulator installed:


New regulator next to old:


New on left, old on right. Brushes are worn down a lot, 64k mi, original part AFAIK


Voltage after install, before test drive:


Voltage after 20 min test drive:


After test drive, engine off. Batt is charging, I think we're OK


So far, so good. Install wasn't hard at all. $$ saved


For the DIY'ers - pelican has a great guide for this (and many other things) HERE