Driving my 01 clk 55 today, which I've owned for 3 weeks now and out of nowhere the BAS, ABS, and overvoltage warnings all came on as well as my car going into limp mode. I did a search and nothing for clk's returned. What I gathered from what I did find was brake light switch, maf, and wheel sensors. Any thoughts before I start throwing money at the problem?

Pull codes from autozone scanner or das star system

Codes pulled. Got voltage malfunction, all 4 oxygen sensors and a fuel trim malfunction. Battery tested bad but it still starts fine. Getting 14v when idling but when I rev it goes upwards of 17v. Thinking overvoltage relay or alternator. Will update tomorrow.

You are close, voltage regulator mounted on alternator, do not drive like this as it will effect the life of your bulbs as well as other electronic parts of your car. As well could boil the battery and cause acid leakage.
Good Luck

Thank you. Voltage regulator ordered overnight shipping. Will replace tomorrow.

Also since you have more money left in your pocket If the battery is also showing bad it could be shorted out inside and will cause grief down the road, even though the car still starts it might be prudent to also change out the battery or batteries if that is the case, unsure if 01 had the small battery inside of the engine compartment as well as the trunk battery or just the engine battery, you will know this I am sure.

Where did you get it from? Just curious.

Magma, I ordered it off of Pelicanparts.com they had a better shipping price than autohausaz.

I just spent an hour at my Auto Hobby shop here on Ft. Bragg where they have lifts and tools to do your auto work. I didn't get anything done. I spent an hour trying to find how to loosen the tension on the belt. I have the new style tensioner but the 17mm bolt is broken off. So I tried finding the right size torx bit and had no luck.

Anyone know what size torx bit is required for the tensioner pulley?

Do not try to remove the tensioner pulley while it is still under tension holding the serpentine belt, when you get near the end of the thread it will break out of the aluminum and damage the front cover of your engine. If you are replacing the tensioner anyways then just carefully cut the serpentine belt off being careful because things will happen quickly when the tension is released. Be careful.

Well I replaced the voltage regulator finally.... did not fix the issue. Although it seems I am no longer getting an overvoltage warning. Just the ABS BAS ESP warnings when I rev past about 3k RPMs. Going to buy a brake light switch and probably buy a new battery, we'll see what that does for me.

Any other thoughts?

Does your car have two batteries, 1 big and 1 small, if so the small one is probably dead or dying, that should take care of the ABS or maybe all. Good luck

Idk. I shall find out.

Replaced brake light switch... no go. Another wasted dollar on a part I didnt need.

Its just weird because its only when I rev it.. so it seems like alternator, but already replaced thr voltage regulator.

Rev it in neutral, Park. Or are talking about 3000 rpm in drive or while being driven?

You must have disconnected the battery when you replaced the regulator, make sure the battery is good, or replace and then turn the steering wheel full left then right to the stops, this should reset some of your lights. Also make sure the brake lights are actually working with the new switch.

Put it in neutral and revved it and it still pops all mafunctions. And then at 4k rpms it starts revving very strangely. See video:


http://youtu.be/buCqnMvmNO0

cannot open the video, but car should have a limiter to restrict the rpms when in neutral.

Did you try the full stop left and right with the steering wheel?

Before I go blow $150+ on a battery.. could a bad battery really cause this issue? Its only when I rev high, and when I rev high it puts way too many volts to the battery (17-18). So I dont wanna buy a new battery and ruin it. I feel like its alternator related but I already replaced the voltage regulator.. scratching my head.

Video set to public now.

The car should not be putting 17 volts into the battery if the regulator is working properly

You said earlier the battery tested bad, with 17 volts hitting it the acid will be boiling and you have probably a foul smell near the battery if you pull off the vent tube, correct.
Was it a Bosch regulator?

The video shows a high voltage making the light go bright, the 4000+rpm surging sound is the rev limiter holding back the rpms because the car is in neutral and the car is protecting the engine from being over revved and causing damage. I believe the alternator is not correct especially if it is putting out 17 volts. Did you use a Bosch regulator?

That kind of looks like a bad battery to me.

The video is from today. Hours after I replaced the volrage regulator with a brand new bosch.