HI,
I have a 96 E300D with 214K on it. The Throttle position sensor code P0120 is on, and i cannot get rid of it. Where is the actual sensor located. I tried calling several dealers and they get confused when I ask for this sensor on the diesel model. They are all unsure about it, and one dealer found the part at $620. Not even sure if that is it. Did anyone have this problem and what did they do to fix it. I heard it could have something to do with the EGR valve, and also the kick down sensor. I am not sure what the kick down sensor does either.

That sensor supplies the pedal position to the computer. Is the car drivable? If so, ignore the error.

As I learned the hard-way, that code can also indicate that the small, short vacuum line from the intake manifold to the TPS sensor has become disconnected! As you face the motor, it will be on your right hand side.

What is this vacuum line? I've had the TPS on my '96 out of the car and it doesn't appear to have a vacuum line. The adjacent transmission vacuum controller does, of course – is that what you mean?

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

There's a vacuum line on the TPS???? If it's there, it must be an OM 606.910,2 thing. On my '98, the TPS is on the driver's side fender well. It looks like a cable on a bell crank. If you have someone press the accelerator when you're looking in that area, you should see it move.

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

That is it. Very expensive but also very unlikely to fail.TPS has a pair of (solid-state) Hall Effect sensors and a couple of magnets. The sensors respond to the changing magnetic field as the shaft that holds the magnets rotates. Both sensors must see the same change.

What is the problem with the car? Does it not want to go or is it just the code? make sure you are not trying to drive with one foot on the brake; the computer will turn off IP control if you do that.

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

As you face the motor, there is a short, small diameter vacuum line that goes from a nipple on the back half of the intake manifold and connects to an electrical unit mounted just to the left inner wall of the housing area where the throttle cable attaches. It is MB part #0105439917. A loose or leaking line here sets the same identical code! My local 'stearlership' replaced the TPS in my '96 E300D when in-fact, it was just this line leaking to whatever part that is.

I posted a picture here that shows what I think you mean, a part with vacuum lines, next to the TPS. That part is the transmission vacuum controller. It simulates gasser manifold vacuum so Mercedes doesn't have to build a completely different transmission just for diesels. I don't know why it would set a TPS code but that system is weird anyway.

BTW, I never did find out where that loose line was supposed to go but I think it's a vent line, lets air into the transmission vacuum controller. I need to find out where it goes.

Jeremy

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

No, that's not the part I was referring to. On my '96 E300D, if you are looking at the motor from the front, on the top right side, but in the rear portion of the manifold, is a short, 1/4 inch diameter, black vacuum line that comes off a nipple on the manifold and attaches to an electrical sensor part that is mounted just inches away on the engine side of the curved, sheet metal compartment housing the TPS and throttle assembly.

I'm going to email PHIL here with that part number. I'm sure he has a schematic and can explain what I'm referring to. But regardless, when the line is not secure, it sets that exact code.

I think you're referring to the MAP sensor. It's just on the engine side of the bulkhead opposite from the TPS. Or possibly the switchover valve for the intake flaps.

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

96E300d here, and I had a code P0120 come up, which seems to be a generic code for a TPS malfunction, but does not mean that the TPS sensor itself is the culprit. After doing some searches, another poster brought up the fact that the TPS is also in a circuit with two other vacuum pressure sensors located on the side of the air filter box. One sensor controls the egr valve, the other the resonance flaps. Also in this vacuum circuit, is that small hose that comes off the intake manifold and feeds into a small black sensor. It seems that all three work in conjunction with one another along with the TPS, and send information to the computer system. In my case, I cleaned off all the electrical connectors at the vacuum pressure sensors, cleared the code, and it has not reappeared. The other thing you should check are all the small vacuum lines that activate the sensors. A leak in one of them could cause a problem. Good luck...
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96 E300d

Yes! That part is the MAP sensor! Thanks to you and Phil at FASTLANE for figuring-out what the heck I was referring to!

Now "kolnerspieler" just needs to check that as a source of his code before spending mega-bucks on a new TPS!

Thank you all for the great responses. I have not been able to do any work on the car yet, but i did do some research and found out some interesting things. According a Mercedes tech the P0120 code in Mercedes terms is P1470 according to a tech on justanswer. It means "a fault for the pressure control flap vacuum transducer". This could be caused by the EGR valve vacuum transducer(which are the little transducers located on the left side of the engine by the EGR valve where the vacuum lines connect to, there are two of them both look the same. one is the EGR valve transducer and the other a Pressure control flap vaccum transducer.) The other thing could be electrical on the right side of the engine . There are two electrical devices, one being the switchover valve, and another which I cannot identify because the picture they sent me is very blurry, but its located right around the EGR sensor and has vaccum lines going to it. The sensor that i can identify is called a modulator pressure switchover valve. I will get an update once i figure out the problem.

The other sensor I was referring to that i could not identify is the MAP, and it is right aroud the TPS sensor. Now I am all excited and I will try to check it out tonight.
Thanks a lot guys, I will update you later on tongiht.

As luck might have it I just got two WIS doc's to test the two transudcers on mine. For me its PO243 but references MB P1_470 too.

PM me your email and I'll send them to you.

__________________
Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)