C240 low idle

bc100

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I have an slightly low idle on my 2001 C240 that occasionaly feels as though it might stall. Is this a simple adjustment?
 

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My understanding is that the idle speed is controlled by the ECU and that it is fixed. However something's causing the low idle speed. Maybe the car needs a star diagnostic to help establish the cause.
Good luck with it.
 

alexanderfoti

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Could need a throttle body clean and adaption reset.
 
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bc100

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Reading further, some people have seen this behaviour linked with accelaration hesitancy which I also have from time to time. This could be due to a MAF sensor fault.
Star would be good but I don't know a local garage that does just a star diagnostic. I have been going to Avantgarde but it is a long way for something that isn't too serious.
 

alexanderfoti

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Ah yes, if you also have drive ability issues, then I would suspect the MAF. If its not bugging you then maybe wait until you have a service due and go to Avantgarde?
 
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bc100

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Is it worth trying to clean it, assuming its dirty of course?
 

AnthonyUK

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Reading further, some people have seen this behaviour linked with accelaration hesitancy which I also have from time to time. This could be due to a MAF sensor fault.
Star would be good but I don't know a local garage that does just a star diagnostic. I have been going to Avantgarde but it is a long way for something that isn't too serious.

A simple check is to ensure the engine cover/filter housing is sitting correctly on the MAF. I had this once after changing the air filters.
 
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bc100

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I'll have a quick look in the morning and report back. Thanks all for speedy replies.
 
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bc100

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I too would suspect the MAF. Nothing to adjust on these engines, but not a lot that controls its running values other than the MAFs either.
So just buy a new MAF then? I'd pop up Steve, but as you know I'm a long way away unless I'm on my way to Bristol.
 

Steve@Avantgarde

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I would still STAR test it, otherwise its nothing more than a best guess. If you are going to replace the MAF, make sure it is a Bosch unit.
 
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