Pete - I'm grinding my teeth because I should have checked your code explanations - not that I'm certain we would have come to another conclusion - I think we were all mislead by your shop saying that they could not manipulate the throttle actuator. In fairness - if they knew what they were doing they should have been able to open & close the throttle electronically if they have the correct test kit. That said.

You could well have a malfunctioning TPS or both TPS & TB. You can take the pedal assembly out of the car & have a go at it - People say they can be revived by a clean up & decent examination. I've only known them to be replaced as is the way these days. Someone posted a thread recently referencing a very old thread & I copied it thank heaven as everyone seems to suffer TPS failure sooner or later.

Here is the pedal breakdown. Well detailed

https://mbworld.org/forums/attachmen...ccelerator.pdf

Here is the pin out with values to check



Regarding interpretation. The problem here lies to some extent with Generic OBDII DTC codes & how Benz translates & uses them. I reluctantly post below Generic & Benz specific codes - I say reluctantly because they can do more to confuse than help & a standard OBDII scanner can't read them the way Benz can with a STAR although to some extent they are cross referenced with the short code if applicable. To make matters worse - Benz put Gasoline codes together with Diesel codes & the same code can mean a different thing on a petrol vehicle to a diesel one. Here goes anyway. Please don't shoot the messenger LOL - & good luck

Generic
P0120 Throttle/Pedal Position Sensor/Switch A Circuit
Malfunction (Generic)



Merc Specific

P0120 Throttle Potentiometer Actuator Actual value, EA/CC/ISC Actuator
P0121 Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance Problem
P0122 Throttle/Pedal Position Sensor/Switch A Circuit low Input
P0123 Throttle/Pedal Position Sensor/Switch A Circuit High Input
P0124 Throttle/Pedal Position Sensor/Switch A Circuit Intermittent

P2100 Throttle Actuator Control Motor Circuit/Open
P2101 Throttle Actuator Control Motor Circuit Range/Performance

P1222 accelerator pedal position sensor B37
P1222 B37 (Pedal value sensor) Sensor 1 Plausibility 1
P1222 B37 (Pedal value sensor) Sensor 1 Plausibility 2
P1222 B37 (Pedal value sensor) Sensor 1 Plausibility 3
p1222 B37 (Pedal value sensor) Sensor 1 The signal voltage is too high.
p1222 B37 (Pedal value sensor) Sensor 1 The signal voltage is too low.
p1222 B37 (Pedal value sensor) Sensor 1 The supply voltage is too high or too low.
P1222 Potentiometer R25/2

P1234 accelerator pedal position sensor B37
P1234 B37 (Pedal value sensor) Sensor 2 IMPLAUSIBLE Sensor 1/2
P1234 B37 (Pedal value sensor) Sensor 2 The signal voltage is too high.
P1234 B37 (Pedal value sensor) Sensor 2 The signal voltage is too low.
P1234 B37 (Pedal value sensor) Sensor 2 The supply voltage is too high or too low.


P2003 Particulate Trap Efficiency Below Threshold (Bank 1) DIESEL!!!
P2004 Particulate Trap Efficiency Below Threshold (Bank 2)

P2004 B2/5 (HFM sensor)(P0100)
P2004 B2/5 (Hot film MAF sensor)(P0100)
P2004 check external voltage supply.Battery voltage too high
P2004 check external voltage supply.Battery voltage too low
P2004 check external voltage supply.Control of holding relay K40/7km (relay CDI) cutoff too early.
P2004 check external voltage supply.KI.15:hardware (HW) turn-on;CAN-BUS turnoff
P2004 check external voltage supply.Relay (diesel engine voltage supply relay) cutoff too late.
P2004 Component N15/3(ETC control module) is faulty.
P2004-001 B18 (high pressure sensor) signal,positive/wire open cause short [P0108]
P2004-002 B18 (high pressure sensor) signal,overload short [P0107]
P2004-004 B18 (high pressure sensor) signal,engine off B28 (pressure sensor) signal
and B18 (high pressure sensor) signal different[P0106]

P2006 B2/5b1 (intake temperature sensor) (P0110)
P2006 check B6/1 (camshaft Hall sensor). Signal too strong. Short to positive
P2006 check B6/1 (camshaft Hall sensor). Signal too weak. Short to ground
P2006 Component N15/3(ETC control module) is faulty.
P2006 fuel pre-supply pressure sensor implausible
P2006 fuel pre-supply pressure sensor signal value too large
P2006 fuel pre-supply pressure sensor signal value too small
P2006-001 B2/5b1 (outside air temperature sensor) signal, positive/wire open cause short [p0113]
P2006-002 B2/5b1 (outside air temperature sensor) signal, overload short [P0112]

 

BTW - I think that the poster of the pin outs has the SP1S & SP2S voltages transposed in red if you read the legend.

 

Wow Glyn, thanks a lot man, this is something I was looking for as I have previously have had the accelerator pedal assembly out of the car, but did not have a break down of it, so didn't pursue to trouble shoot it. As you mentioned in your opening statement, I do agree, they should have know what they were doing, which was the interpretation I got when they said that they could not manipulate the TB with "whatever" scan tool/diag. system they were using. Now, I asked the shop before if they had a SDS, and they said no, but that they had something "close to it". So, it looks like I should pursue the TPS then. I will pull the assembly from the car, take apart and clean as you mention, and, if I have no luck doing that, I guess I'll be getting a new TPS. Thanks again for your detail explanation on this subject.

 

Pete, Here's the rest - lost in the middle of that stupid sprintbooster thread.

 

Thanks again! It is saved. I went out, took the pedal assembly out of the car and brought it in to examine/clean. The sensor itself is held in with some sort of white colored epoxy. I took the two screws off, yet it would not come out of the pedal assembly. I actually had to pry it off with a big screw driver breaking the "white epoxy". I sprayed some electronic cleaner in there and on the 6-pin connector. Put it back together and back in the car. No results. Now, I did try something different to see if there would be any effect, but none. I kept the TPS unplugged and started the car, still the erratic idle and ESP error. I'm guessing that there is a constant value or voltage/resistance that is required FROM the TPS in order for it NOT to trigger a CEL. Again, this is just an assumption on my part. Gyln or anyone else, would you know if this is the case for certain? I must say, this is quite frustrating. Could it be the wiring harness as well?

 

That pedal sensor is not simple....not that you would expect anything different from MB. Some transistors and a hall element. I assume you are going to replace it now?

 

You assume correctly. I figured it was at the point where I would either make it work, or have to replace it anyways, so I went for broke. Now, to see if I have to replace the WHOLE assembly or not and what it will cost. I guess I'm gonna go to the MB dealership on Monday and see if they have one in stock or not.

 

I found it on line for $159...............

 

The sensor is available on it's own here in SA - lucky it's not a BMW or you would pay $600.

I've never done it but can you disassemble the thing & replace the two trannies in it or is that part encapsulated? The hall motor should not fail. Have you measured voltages.

The only reason I ask is that the TB actuator comes apart & can be repaired by a handy person.

 

So after putting on a NEW Throttle Actuator and a NEW Throttle Positioning Sensor (Pedal Assembly), I can say that none of this has fixed my problem. I gave up and drove it to the MB dealership today. They called me up and said that they were leaning towards the Throttle Actuator. I told them that that can not be it, since I replaced it with a brand new one. So then the SA said that it may just be the wiring or the plugs and that they are going to try to clean the contacts and see if that works. Well, we'll see what happens. Oh yeah, I also have a broken rear coil spring, woo hoo. It won't pass inspection with the spring like that, they quoted me $502 for that job.

 

bummer pete. =(

 

You are not having much luck are you????? Damn

 

These are times that try men's souls. Despite all the dealer's experience and diagnostics they're obviously stumped too.

 

Any update on your MAF / throttle body / TPS / rough idle problems?

 

Yes, actually, there is! I ended up taking the car to the MB Dealership where I bought my car, Mercedes Benz of West Chester (PA, not NY). They had the car for a week messing with it. Turns out (according to the SA) that the little pin connectors (female ends) needed to be replaced on the plug that plugs into the Throttle body, aka Throttle Actuator. So they did that and test drove it and said that the problem did not return. Which they are correct, I haven't had that same problem now since I got it back. Here is the real kick in the nuts though, I made the mistake of taking to the dealership as my last resort, AFTER I bought the suspect parts, a new throttle body ($440) and a new Throttle Pedal Assembly (which contains the TPS, $228). So, I have these new parts which I technically did not need. I will still more than likely put them on the car and keep the still functioning parts as spares.

EDIT: I would also like to thank everyone who contributed to this thread in your opinions and involvement with helping me with this problem.

 

Glad you got resolution, Pete.

The old parts will make excellent paperweights.

 

What a pain in the @$$ - I got shouted down by some on the 204 forum a while back for suggesting that people should not wash their engines with a hose. Wish they could see this. I have little doubt that the problem was corrosion.

 

Yes they will! Not to mention pricey! Thanks man!

To be honest, I never wash my engine bay. What I DO though, is use a damp cloth to wipe down any dirt and grime. Yeah, I'm guessing either corrosion, or the pins were just weak and stretched out. I'll tell you what, that was a problem that seemed to be hard to track down. Again, I couldn't find it, the independent shop I took it to couldn't find it, and it took the MB dealership a week to resolve it. All for some connector pins that weren't making contact.

 

Yeah - I'm not saying you wash your engine but those that do risk trouble later in the vehicles life. My service manager says they love people that wash their engines. Make lots of money out of them. MBSA has banned dealers from washing engines. They just do a wipedown with some MB non silicone spray & cloths. Silicone spray is another absolute no - no. Poisons the O2 sensors. People think all those connectors are waterproof - not so.

 

I am having the same issue currently, P0120, my 2003 C230 6spd. is in limp mode. This is the third time this has happened over a month period, 1st two times I was able to get it to work again, 3rd time not so lucky, it sucked as I was 40 miles from home on a Friday night, drove home in limp mode on the freeway (40mph in 6th gear, 1500 RPM).

I now have 2 throttle pedal assemblies. When I plugged in the new pedal assembly, the car worked just fine, out of limp mode, reved it up to 3000+ RPM had it idle for 5 min, turned it off, sat for 2 minutes, turned it on, back in limp mode, same CEL.


Tested all 5 wires for continuity from the TPS to the PCM. Checked both grounds, 5v supply, and TPS voltage outputs, all seem within spec.


Buying some files to clean the PCM "F" female connectors (all) and the female connector to the TPS after reading this tread. I will also take a look at the TB connector as well. If that doesn't work, having a shop take a look at it after I give them the whole long story as I will have exhausted my abilities.

Followed this TPS testing thread.
http://forums.mercedesclub.org.uk/sh...ad.php?t=50319


I'll update later this week. This is currently the bane of my existence.




- John

 

Another good resource for the P0120 CEL

https://mbworld.org/forums/c-class-w...-speed-17.html


Bottom of page 17, two PDFs, last one is error possibilities.