jturkel

ugh.....i hate the electronics on this car. perhaps its because when one thing goes, other things go

i replaced my battery a couple of months ago. so its pretty new. two nights ago, after about a 50 minute drive, i pull into a parking spot and up comes

"Under Voltage Consumer Defective"

crap. ok. i come back an hour or so later, it turns over. ok good. i monitor the voltage. seems to be in the high 12s range: 12.6-12.9 for most of the drive back.

yesterday, voltage was in the mid to low 13s: 13.0 - 13.5 for most of the time.

today, voltage is everywhere: i've seen 13.5, 12.5 and 11.9........started off higher and as i drove, dropped into high 12s, then lower 12s. it is starting to hesitate to turn over on startup

so i'm wondering, is this an alternator issue?

i have NOT gotten that error message again
like i said, basically a brand new battery
i monitor battery voltage (my readings) through OBDII
i have updated seat modules

also, if it IS an alternator issue, which one do you guys recommend/is the right one? i dont want to deal with incorrect pulley issues and such (8 rib vs 6 rib)
i searched and found some links:

http://www.bimmerspecialist.com/part...54-02-02%2088#

http://catalog.worldpac.com/ibusines...art=Alternator

also see post 18: https://mbworld.org/forums/c32-amg-c...ternators.html

thanks for your help guys.....

jturkel

just got it down to 11.7 V while driving. over a course of two miles, battery voltage while running consistently got lower and lower. on the way back, i was hitting between 11.7 and 12.0....then it randomly jumped up to 12.5 for a little while and then back down.

and i got the under voltage consumer defective error message again.

Quicktwinturbo

voltage regulator perhaps?

loungn14

Its the alternator/regulator josh......same exact symptoms when I had my car...

ScottW911

Uhh, your problem is obvious. The message was just missing a comma.

TemjinX2

your alternator is dead. You need to replace it.

jturkel

ok so quick question.

today it was fine and in the 13s all day and (and 12.9s). i ordered the alternator anyway. is this normal behavior as it goes out? one day it might be perfectly fine and the next day it is everywhere?

Quicktwinturbo

Check and see if it's your regulator.. Mine did the same...

jturkel

i had the alternator and battery tested today. results came out fine, but i'm not satisfied with that. i know something is wrong. it happened to be working fine at that exact moment

TemjinX2

the c32 regulator isn't replaceable. The c55 and newer w203's have a replaceable regulator.

Beaker

I have gotten this error twice as well in two days..

The only variable I can bring my down to is a wet engine bay causing a short circuit.

We have been very dry lately here until the last couple of days we have had massive down pours of rain and i park my car on a hill (facing down). I have removed the weather striping from the car so the engine area gets wet.. even though there is the spill tray for the battery cover I'm still unsure..

The weird thing is the error message today didn't come on today, it came on this afternoon on the drive home.. but once again iti was raining heavily all day.

Maybe my alternator is going but I'm also sceptical and think it could be something else.. just wish i could monitor battery voltage.

jturkel

Beaker,

you can monitor battery voltage through the "super secret menu" accessed through using your A/C buttons.

i monitor it through my OBDII gauge though.

and it hasnt been raining here, so i'm not sure that is what it could be. i have been told that the alternator usually goes about between 80-90 and i'm just about to hit 90k. so.... pff...i just hope that it is what it is....or else i just bought an alternator for nothing.

Beaker

Yeah fair call..

Yeah well I'm on 106k so it probably sounds right too for mine.

Does yours come on every time you drive and random intervals or is it a set sequence that you know it's going to come on (ie/ 2mins after car starts or something)

Both times for me it has come on in heavy traffic with the engine idling (and it sounded like it was idling too low too just before it came on).. so the alternator theory works with what happened to me.

jturkel

something else.....

voltage started high again and over the course of the day, has dropped to consistent low 12s and high 11s.

BUT, i did notice my coolant temps and air temps were at least 10 degrees warmer than usual today....on a 66 degree day.

how does this logic sound? alternator on the way out, so more voltage being drained from the battery BUT to help prevent that and work with the less voltage, the fan is affected....either comes on later or spins slower, and thus uses less energy? thoughts?

either way, alternator comes in tomorrow and i'll be doing the install likely on saturday

TemjinX2

your temps are probably higher since your fan probably isn't as spinning as fast and your intercooler pump isn't pumping the coolant as quickly as usual due to the low voltage.

I would just replace the alternator and see what happens. Since your problem is essentially power generation.

jturkel

yah thats what i'm thinking. thanks. alternator is coming in tomorrow morning and i'll get around to installing it saturday morning/afternoon.

Beaker

how often are you getting the warnings and engine cut offs?

jturkel

no engine cut offs....yet. i've gottent he warnings three times. once on saturday. no times on sunday. then twice on monday (or tuesday, i don remember). and none since yesterday.

Beaker

hmm odd..

the two times it happened to me It cut my engine off as it was idling low.. see was the mechanic say I suppose.

jturkel

and you got the under voltage message? interesting. the only time my engine was put into LIMP mode was when i needed to get a new battery and it barely had enough power to turn over.

TemjinX2

you guys are lucky. I didnt have any warning signs. Mine just died.

jturkel

weird

i just got my alternator. i'll install it tomorrow and report back to see if my problems are solved.

voltage today started at mid 13s. stayed there for 15 minutes. dropped to mid-high 12s for 30. and then low 12s for another 25 minutes. and then dropped down to 11.7-12.3 range for a minute.

anyone know the avg/correct running voltage during driving?

Phil C55

On any healthy 12V automotive system the voltage will run at 13.8-14 volts. My son has a car that we bought cheap because of a charging problem that the previous owner gave up on. They installed a new battery and a new alternator but still had issues. Sometimes it was low then way too high and after another alternator it was doing the same thing. Turned out that the problem was a loose post on the starter solenoid where the lead from the alternator was attached. Took it all apart, tightened everything and it has been putting out a steady 13.8-14 for the last two years and no more issues.

jturkel

interesting. so where is the starter solenoid on the W203? i'm guessing near the alternator? should i just look for loose stuff in that general area?

Phil C55

I'm not suggesting you look elsewhere, your problem may just be the

alternator, what I was trying to point out is sometimes it's not what we

think at first. That said, any starter solenoid is attached to the starter

since it's the solenoid that engages the starter to the flywheel so it can

turn the engine over. On my sons car I just followed every cable from the

ground at the battery to the positive cable to all cables on the alternator.

Checking stuff is free and sometimes you stumble onto what's wrong.

Sometimes it's just a failed part. Before I bought a new alternator though,

I would take mine off and have it tested for free at any auto parts store.

No return policy on most electrical parts and if yours checks out, you just

saved $400.