W204 C220 CDI - throttle valve 100%

[MrNakamura]

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.

 

[Dodipops]

What happens to the throttle data at WOT? Does it go to 0% might just be the way the data is being displayed.

 

[MrNakamura]

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.

 

[MrNakamura]

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).

 

[alecmascot]

2008 was a change over year... which engine do you have ? 646 or 651

 

[MrNakamura]

Hi - It’s the 646

 

[alecmascot]

Sadly I cannot find that value on my MB2.0 ??

 

[MrNakamura]

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.

 

[alecmascot]

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.