W204 C220 CDI - throttle valve 100%

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MrNakamura

New Member
Joined
Jan 9, 2020
Messages
6
Location
Twickenham
Car
2008 C220 CDI
Morning all

Both OBD and the Mercedes Me app showing throttle valve at 100% all the time.
Car drives fine, but rough for ~5 secs just after switch on at idle until given a bit of gas, like it’s struggling to get to 1000rpm.

Didn’t want to link 2 issues that might be unrelated, but wondered if anyone has seen similar. Current theory is the throttle valve butterfly actuator or EGR.
 
What happens to the throttle data at WOT? Does it go to 0% might just be the way the data is being displayed.
 
Thanks, will check tomorrow - I don’t think it’s ever shown anything other than 100%, but will give it a good floor and see.
 
Morning, had the app running all the way to work this morning - never showed anything other than 100%, regardless off full throttle - 100% right from engine on (cold). Double checked with the obd scanner (TP %) when arrived (so engine hot but idling) that saying the same. So at least this isn’t some app weirdness. If anyone else has a 220CDI, I’d be interested if yours shows anything than 100%. What I can confirm is that throttle pedal sensors (APP_D and APP_E) are ok (which I would expect given it drives fine).
 
2008 was a change over year... which engine do you have ? 646 or 651
 
Thanks Alec for looking. Being a diesel, then I did wonder if the throttle valve always being open (if open means 100%) is totally normal - just can’t shake the feeling that something may be off - especially knowing how most components on the intake system get carboned up.
 
In a diesel the only use for a throttle is to close when the engine is turned off to prevent any over-running.
I doubt there is anything wrong with what you are seeing.
 

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