C220 om646 w204 different idle rpm value.

[piotreus]

Hi. Recenty i have noticed that sometimes the idle rpm value are differnt. Once in the same circumstances( a/c turn off) rpm value are 750 another time 850 rpm. Today when i was driving to the shop the rpm was at 850 rpm and it was ranining.after i stopped I pushed off button to turn off thermatic the rpm value fall down to 750 rpm. It looks like the a/c is tunr on even if it is turned off ( the a/c button is'nt Flash). Ater i finished my shopping and drove back home( without rain) the rpm was at 750.
Does anyone has any idea why is it hannepning? I dont know if i shlould worry. Does the weather has imapct on it?
Thx in advance.
First photo rain; second without rain both a/c turned off

 

[se97mlm]

It is a software bug. Don't worry. Normally it should be at 780rpm with AC off and 880 with AC on. Sometimes it falls to 780 although AC is on. If you push hard on the brake pedal or rev to idle speed plus 200rpm it will settle at the right speed again
Regards
Matt

 

[piotreus]

Ok thx a lot. I thougt thah maybe it is a dpf regeneration process but i instaled a red light as one of our forum membran but it didnt flashing then. So i thought i made sth wrong but now i know it's ok.

 

[piotreus]

Hi it's me again i'm still thinking about this and i'm wondering why is it that.
I attached below short movie to show you exactly ha itp look like.

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[piotreus]

Hi it's me again i'm still thinking about this and i'm wondering why is it that.
I attached below short movie to show you exactly ha itp look like.

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Accept third party cookies

I find out why it is happens. Its because of the PTC heater. So everything is ok.

 

[Brian220CDI]

Drain on the battery so the engine is speeding up to create extra charge maybe? Lights on rear window heater on etc can all drain the battery a little.

 

[piotreus]

Hi guys. Its a long time since my firts post. I am still wondering if everything is ok. Sicne autum i have higher rpm all the time at 900rpm. Is it really normal? A/C is off but the rpm is still higher. I understand it js becasue of ptc but should it be turn on all the time despite the engine temp? For me it should turn off the when te engine is warm enough to heat the air by its own..

Still looking for help..

 

[Mato84]

Čaute ľudia. Od môjho prvého príspevku je to už dávno. Stále sa pýtam, či je všetko v poriadku. Sicne autum mám stále vyššie otáčky pri 900 ot./min. Je to naozaj normálne? Klimatizácia je vypnutá, ale otáčky sú stále vyššie. Chápem to js kvôli ptc, ale mal by byť zapnutý stále aj napriek teplote motora? Podľa mňa by sa malo vypnúť, keď je motor dostatočne zahriaty na to, aby ohrieval vzduch sám.

Stále hľadám pomoc..

Hello, ! I have this problem on my 220cdi too , IT IS fixed? Thanks