c230K Engine Problem
Thread Starter
Junior Member
Joined: Jan 2012
Posts: 18
Likes: 0
From: Bay Area, CA
W205 C63 Cabriolet
c230K Engine Problem
Hi guys I'm new to this forum and I certainly didn't want this problem to be my first post here, but here it is. I've searched high and low in these threads for an issue remotely similar to mine but haven't found it. I drive a 2002 c230 coupe and I'm having a really wierd issue with the engine. The thing is when I'm driving normally everything is fine, but when I turn on the climate control or fan or whatever, it starts sucking power from the engine, making it work a lil harder and giving it jumpy revs. I takes so much power that I can see my headlights dimming at night when I turn my fan on. But other than that, when it isn't on, it drives normally.. please help?
Super Moderator
Joined: Jun 2008
Posts: 19,942
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Hmm! - Is it only when you turn on the Aircon or other accessories as well? The aircon does use quite a lot of engine power to drive & can cause rough idle if the engine is not in a perfect state of tune.
You do however say that lights dim and I'm not sure whether it's due to very low idle or a battery/charging problem.
Have your battery load tested & charge rate & regulator checked. Alternator or battery or both might be getting tired.
Welcome!
You do however say that lights dim and I'm not sure whether it's due to very low idle or a battery/charging problem.
Have your battery load tested & charge rate & regulator checked. Alternator or battery or both might be getting tired.
Welcome!
Thread Starter
Junior Member
Joined: Jan 2012
Posts: 18
Likes: 0
From: Bay Area, CA
W205 C63 Cabriolet
Ok scratch that. I started the car this morning and it was doing it without turning on the aircon as well. Later this week I'll go to my friend who's a mechanic and he'll let me use his OBDII for free. And actually it doesn't just occur at idle. It will do it sometimes when I'm driving whether it's on the road or freeway. The battery was changed by MB earlier this year so it can't be the battery..
Last edited by JsCoupe; Jan 24, 2012 at 07:32 PM. Reason: Forgot some info.
Super Moderator
Joined: Jun 2008
Posts: 19,942
Likes: 191
From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
It could still be the battery (new batteries fail) but sounds more like an alternator.
Post codes when you have them.
Good luck!
Post codes when you have them.
Good luck!
Thread Starter
Junior Member
Joined: Jan 2012
Posts: 18
Likes: 0
From: Bay Area, CA
W205 C63 Cabriolet
Alright, so I took the car to my friend who's a mechanic, and he hooked up the voltometer and what not. At first it was fine but then when he told me to rev to about 2000 rpm he found the problem was with the diodes in the alternator. Apparently the messed up alternator is screwing around with the current so it's causing improper revs, power loss etc. So now that it's been figured out, where can I find an inexpensive alternator for the m111?
