BenzKompressor

So, I replaced the battery (was way overdue) only to have what I call "throttle puke" come back on the second start. Took the car to a friend who has the Snapon diagnostic "machine" with MB software package... he pulled a bunch of different codes that pointed to the throttle itself. After he reset the codes, I didn't have the issue return.
At this point, I've concluded the weak battery was the cause and the computer(s) needed reset with a proper diagnostic tool... as the check engine light did NOT go out after the battery was replaced. I guess time will tell if the P0120 'throttle puke' has been cured. But, so far so good!

I also had rich mixture AND lean mixture codes along with a misfire on all 4 cylinders! After some hard driving and the reset, those seem to have been cured as well! :-) Luckily this engine only has two O2 sensors, unlike my '01 Jeep XJ (Cherokee) which has FIVE. But it does have 3 cats (yes I can spell catalytic converter [or convertor, depending on which side of the ocean you're on!] without spell check lol) as opposed to the single one attached to the M271 :-)

Glyn M Ruck

A bad battery can cause the Throttle pedal to lose synch with the throttle plate (butterfly) with the "fly by wire" throttle. Let us know how things progress.

BenzKompressor

I have P2119 'Throttle body out of range' coming back every time I reset the codes. I did have a stored code, previously, that had the description "throttle return spring", but that is not coming back. That was before I cleared the codes AFTER my battery replacement. SOLELY P2119 is what I've got, with no pending codes. It takes about 3-4 days, and maybe 25+ drive cycles to come back after resetting the codes.

I have ordered a Mercedes SDS (Star Diagnostic) C3, possibly getting a C4 (seller said they offer all C3 buyers a C4) if it's the same price... So hopefully I can get to the bottom of it with that diagnostic system.

I am betting it is the throttle body that needs replaced. But with the weak battery, it was tripping P0120 (instead of my lone P2119) and causing the "throttle puke" condition (as I call it). That is my theory as of yet.

The dealer wants $1100+ for the throttle body, parts geek has a Bosch for something like $550. I haven't done an extensive search (YET) for the best price. But so far it's looking like I'm definitely NOT going with the dealer for this. I only go to the dealer for parts that I need RIGHT NOW, and luckily so far those parts have been $10 or less!! :-)
I'm not going to do any heavy parts shopping for the best price/quality until I am sure what the real problem is.

Anybody know if the Air Recirculating flap and the Throttle are interchangeable? They look exactly the same (physically), but have a different part number and about $200 difference in price. I'm guessing internally they are different.

Oh yeah, and my lean mixture code has gone away with replacement of the upstream lambda (O2) sensor! :-)