SLK-Class (R170) 1998-2003: SLK 200, SLK 230K, SLK 320

SLK/R170: '01 slk320 P0120 code, significant loss of power!!! HELP!!!!

Old Mar 14, 2008 | 03:59 AM
  #1  
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'01 slk320 P0120 code, significant loss of power!!! HELP!!!!

The battery was disconnected in my 2001 slk320 (6speed manual) for a while. After I started, car sounds fine idles normally, but when you start driving there is almost no power until like 3K rpm. Same when it is in neutral, I step on gas pedal for like a second nothing happens, then the tachometer gauge start moving very slowly. Check engine light is on - I checked the codes: P0120 "Throttle valve potentiometer malfunction".
Is the problem in pedal assembly or somewhere else?
Would appreciate any info on that.
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Old Mar 14, 2008 | 12:11 PM
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slk
Try a reset its free.

Turn the key to the on (not start) position, the position just before the starter turns over.

Press the gas pedal to the floor with the key in the "on" position.

Hold the pedal to the floor for five seconds, then turn the key back
to the "off" position (don't remove the key), then release the gas
pedal.

Wait 2 mins. for a full alignment.

But if that does not work, sorry to say its probs the TPS that has failed, Removing the slk batt is never without risk, unless you fit a anti-spike.

About $200 odd for new TPS.
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Old Mar 15, 2008 | 10:03 PM
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thax for the info, i will try that tonight. If it is TPS do you know where is it in slk?
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Old Mar 16, 2008 | 09:56 AM
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Few other things to look at also, to narrow it down more.
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Old Mar 16, 2008 | 11:40 PM
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what other things you mean???
by the way I tried to reset, as you suggested, didn't work ;-(
I ordered a new pedal assembly hope it will fix it, if not - i guess my next step will be throttle body. If I'm wrong please let me know.
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Old Mar 17, 2008 | 01:05 AM
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300E a couple 1994 w124wagon E320 Wagon/,1971MGB Track/Rally, MG Midget Autocross ,2000 E320 wagon.
TPS is

in the throttle body,make sure all wires are good.Before you start throwing parts at it i.e. pedal assembly get it to an indie shop with a real time scanner that can determine if the tps is indicating the right output to the ecu.You do't have the proper scanner to do the diagnostics,so a few bucks to have it properly traced will pay off in not tossing in a bunch of pricey needless parts.And this is coming from a member that has the tools and such and never goes to a shop,but would hate to see you spend more time and money chasing down the wrong issues.
Did you have the problem before the battery was disconnected?Have you charged the battery fully like over night at 10 amps?After you do the above and check that the battery is good,do the other reset that helps at times.Disconnect the battery step on the brake pedal for 30 seconds rehook up the battery and follow the resync procedures in your manual in the battery area for what to do after a battery is installed.
sometimes if it was a temporary condition caused by the battery system this will reset the tps gremlin
good luck
ohlord
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Old Mar 17, 2008 | 05:32 AM
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Check you PMs, K40 relay is one thing to look at.
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Old Mar 17, 2008 | 12:41 PM
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Thanks guys. I'll try all that, I'll keep you posted.
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Old Mar 17, 2008 | 05:37 PM
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Dont just go buying loads of stuff, lets find out what it is first m8.
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Old Mar 18, 2008 | 02:44 AM
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Thank you guys for support!!!!!!! I replaced today the pedal assembly and everything went back to normal. I guess, I got lucky and ordered the right part.
By the way if somebody has an AMG front bomper for sale, I'll consider the offer.
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