P0120 & Limp Mode
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S600 - 2003
P0120 & Limp Mode
After a torrential downpour a week or so ago at work, I went to drive my car home and got the P0120 code. No leaks noted in the car. The night prior, I had reinstalled a new driver rear wheel/tire after one of the firehawks had been punctured. Come to think of it, I actually swapped the tires left to right in the rear also so the new tread would be passenger rear. Doing this in the dark in the car port, perhaps I knicked a wheel sensor?
I did order and just replace the pedal position sensor on the car. Problem is not resolved.
My reasonable next step is to order replacement wheel sensor.
What other options can I be tracking down? OBD2 lists P0120. Inside the car, it reads Pre Safe something or other not working, and ESP malfunction.
Symptom is no throttle input. Warning messages come up. Idle is smooth at first, then a bit choppy. Full throttling the pedal gives me maybe 1500 to 2000 rpm and what feels like super rich / safe or very minimal TPS percentage.
I did order and just replace the pedal position sensor on the car. Problem is not resolved.
My reasonable next step is to order replacement wheel sensor.
What other options can I be tracking down? OBD2 lists P0120. Inside the car, it reads Pre Safe something or other not working, and ESP malfunction.
Symptom is no throttle input. Warning messages come up. Idle is smooth at first, then a bit choppy. Full throttling the pedal gives me maybe 1500 to 2000 rpm and what feels like super rich / safe or very minimal TPS percentage.
Super Member
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From: Montreal, Quebec
2009 E350 4M Avantgarde;mistress 2002 S600; wife 2014 C300 4M
P120 is throttle circuit. Since you already change the pedal xmtr, the throttle body or wiring is next. Not sure you actually need to reset with SDS.
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S600 - 2003
I did also install a new battery from the recommended list several weeks prior to this. No negative symptoms notes. All settings relearned.
TB itself. I wonder what those go for?
I did a precursory look in the engine bay tonight before the light faded. Nothing was loose. I disconnected and reconnected the TB harness. No change.
TB itself. I wonder what those go for?
I did a precursory look in the engine bay tonight before the light faded. Nothing was loose. I disconnected and reconnected the TB harness. No change.
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S600 - 2003
Does anyone know the part number for the sensor? Commonly available at Autozone?
Got sidelined.... driving the SC'd vette and got rear-ended the other night. Living on pain meds with concussion for a little while.
Got sidelined.... driving the SC'd vette and got rear-ended the other night. Living on pain meds with concussion for a little while.
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S600 - 2003
Ordered new left and right rear abs speed sensors. They should be in tomorrow, so hopefully tomorrow night I will know what it up with this BS.
Still open to other ideas. Am down the garage now, so going to pull the rear wheels and look at the existing sensors - maybe try cleaning them up and reseating them to see if anything changes.
Still open to other ideas. Am down the garage now, so going to pull the rear wheels and look at the existing sensors - maybe try cleaning them up and reseating them to see if anything changes.
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S600 - 2003
Popped the wheels off.
Seeing where those sensors are now on my car, there is no way I touched them. They still have an even film of road dust, too, so no contact.
I will still replace the sensors when they come in.
Thoughts? Advice? What else can I be checking? Not a lot of chiming in on this post. If it were the TB, how can I test that or verify?
Seeing where those sensors are now on my car, there is no way I touched them. They still have an even film of road dust, too, so no contact.
I will still replace the sensors when they come in.
Thoughts? Advice? What else can I be checking? Not a lot of chiming in on this post. If it were the TB, how can I test that or verify?
Senior Member
Joined: Dec 2010
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From: Virginia Beach
2005 S600 2005 SL600
"After a torrential downpour"...
Then you have electrical gremlins?
I would start by pulling the screen off your airbox intake (for the climate control) and looking down at the reed valve/drain in the bottom. See any gunk in there? Or is it bone dry and clean?
Then you have electrical gremlins?
I would start by pulling the screen off your airbox intake (for the climate control) and looking down at the reed valve/drain in the bottom. See any gunk in there? Or is it bone dry and clean?
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S600 - 2003
I checked the drain system, it is not retaining water. I happened to check it while the car was outside in moderate rain.
I bought a replacement TB from a 2006 instead of coughing up for new right off the bat. I just finished installing it, and there is no difference or change. The car starts, goes into cold idle, then after short amount of time goes into ESP inactive. At no point is throttle input from the pedal accepted.
Now the gremlin hunt begins.
Is there anyone in the northeast / CT area I can approach for this one instead of a dealer?
The car is still only throwing the one P0120 code.
At this point, I am frustrated. Anyone think it could be the speed sensors? I have not installed the new ones yet. I will have some time to look at the car on Sunday again finally.
I bought a replacement TB from a 2006 instead of coughing up for new right off the bat. I just finished installing it, and there is no difference or change. The car starts, goes into cold idle, then after short amount of time goes into ESP inactive. At no point is throttle input from the pedal accepted.
Now the gremlin hunt begins.
Is there anyone in the northeast / CT area I can approach for this one instead of a dealer?
The car is still only throwing the one P0120 code.
At this point, I am frustrated. Anyone think it could be the speed sensors? I have not installed the new ones yet. I will have some time to look at the car on Sunday again finally.
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Thread Starter
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S600 - 2003
In searching other forums, there is commentary sharing that any time a new TPS and/or TB are installed, the car must re-learn their ranges and stops. Further, that there is a specific re-learn process to be done. I have not tried this yet, and cannot tomorrow since it will be pouring all day here. With luck, I can give it a try on Weds or Thurs since both parts have been replaced now on my car. I may also disconnect / reconnect the battery beforehand to see if that has any impact whatsoever.
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S600 - 2003
Latest update. I threw in the towel since the weather is shifting here and the Corvette needs to be parked soon. I had the car flat bedded to the local dealer and they diagnosed it.
Having gone over the car and tested all the pin-outs to be working, they determined that the throttle body is dead and must be replaced.
They offered that they could have a replacement on-hand and do the repair this week for $2,600. Knowing MB charges $900 or more for the part and the job is about an hour, maybe two by the shop book guide there, I am guessing overnight shipping would be the catch. In either case, I know I can get the part for $522 brand new from Bosch on Amazon and I will do that.
Odd that my oem TB went... and the tested / functioning TB I bought from E-bay is also dead... I must wonder if the MB tech did sufficient hunting before tossing the $2,600 quote at me for a TB swap, but I will follow through on it. I will also approach the parts guy and see what he can do for me, since he sometimes knocks off shipping and gives the military discount which helps before diving on the Amazon option.
Having gone over the car and tested all the pin-outs to be working, they determined that the throttle body is dead and must be replaced.
They offered that they could have a replacement on-hand and do the repair this week for $2,600. Knowing MB charges $900 or more for the part and the job is about an hour, maybe two by the shop book guide there, I am guessing overnight shipping would be the catch. In either case, I know I can get the part for $522 brand new from Bosch on Amazon and I will do that.
Odd that my oem TB went... and the tested / functioning TB I bought from E-bay is also dead... I must wonder if the MB tech did sufficient hunting before tossing the $2,600 quote at me for a TB swap, but I will follow through on it. I will also approach the parts guy and see what he can do for me, since he sometimes knocks off shipping and gives the military discount which helps before diving on the Amazon option.
Super Member
Joined: Sep 2012
Posts: 690
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From: Montreal, Quebec
2009 E350 4M Avantgarde;mistress 2002 S600; wife 2014 C300 4M
ask the dealer what specific faults have been flagged by their test equipment, before you throw any more parts at it.
Somewhere on this forum is the reset procedure for the throttle circuit (I believe in the "stickies") - search!
Good luck!
Throttle body motor travel can be "read" with SDS.
Somewhere on this forum is the reset procedure for the throttle circuit (I believe in the "stickies") - search!
Good luck!
Throttle body motor travel can be "read" with SDS.
Super Member
Joined: Sep 2012
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From: Montreal, Quebec
2009 E350 4M Avantgarde;mistress 2002 S600; wife 2014 C300 4M
Independent garages may also have such a system.
Update your member info with your location - members here often have that equipment.
Last edited by kraut56; Nov 20, 2018 at 01:56 PM.
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S600 - 2003
I'm up in Connecticut. I picked the car up from the dealer tonight. Their pricing turned out to be very fair on labor, it was just that their price for the part was three times what it sells for on Amazon. If they could have got it in the ballpark I would have given MB the business.
OK, so sds is like what I have for my gm as a tech 2 or 3 access system which communicates with all the systems / modules on the car and can reprogram them. Sounds handy on such an electronics-forward car.
I placed the order tonight for the new tb after reading through the techs notes. Delivery date uncertain, but should be about 2 weeks. I may break down my original one in that time just to see how it works and what may have failed.
OK, so sds is like what I have for my gm as a tech 2 or 3 access system which communicates with all the systems / modules on the car and can reprogram them. Sounds handy on such an electronics-forward car.
I placed the order tonight for the new tb after reading through the techs notes. Delivery date uncertain, but should be about 2 weeks. I may break down my original one in that time just to see how it works and what may have failed.
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Mercedes
I'm up in Connecticut. I picked the car up from the dealer tonight. Their pricing turned out to be very fair on labor, it was just that their price for the part was three times what it sells for on Amazon. If they could have got it in the ballpark I would have given MB the business.
OK, so sds is like what I have for my gm as a tech 2 or 3 access system which communicates with all the systems / modules on the car and can reprogram them. Sounds handy on such an electronics-forward car.
I placed the order tonight for the new tb after reading through the techs notes. Delivery date uncertain, but should be about 2 weeks. I may break down my original one in that time just to see how it works and what may have failed.
OK, so sds is like what I have for my gm as a tech 2 or 3 access system which communicates with all the systems / modules on the car and can reprogram them. Sounds handy on such an electronics-forward car.
I placed the order tonight for the new tb after reading through the techs notes. Delivery date uncertain, but should be about 2 weeks. I may break down my original one in that time just to see how it works and what may have failed.
Super Member
Joined: Sep 2012
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From: Montreal, Quebec
2009 E350 4M Avantgarde;mistress 2002 S600; wife 2014 C300 4M
Buy yourself an SDS system (chinese, but plug and play) or find an indy that has one, before you throw any more parts at it.
You can browse/search this forum for SDS systems.
You can browse/search this forum for SDS systems.
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S600 - 2003
Continuing chronicles.
Delt with a concussion from a car accident and recovered. Also moved since my last post, so I've been busy. But the car goes to the dealer next Monday again now that I have tried three (factory original and two used pieces) throttle bodies and the problem persists. I want the dealer to confirm for me that the signal is correct and reaching the throttle body. Partly to say I told you so, and partly to slap them for suggesting I spend $2600 to buy/install a brand new TB to definitely solve the issue. Yeah, ok.
But I've finally got a big garage to work in, so if I have to rewire or chase it down over the winter on my own I can. That may be exactly how it goes down. No other new codes or issues. Just idle with no throttle input. Annoying.
Delt with a concussion from a car accident and recovered. Also moved since my last post, so I've been busy. But the car goes to the dealer next Monday again now that I have tried three (factory original and two used pieces) throttle bodies and the problem persists. I want the dealer to confirm for me that the signal is correct and reaching the throttle body. Partly to say I told you so, and partly to slap them for suggesting I spend $2600 to buy/install a brand new TB to definitely solve the issue. Yeah, ok.
But I've finally got a big garage to work in, so if I have to rewire or chase it down over the winter on my own I can. That may be exactly how it goes down. No other new codes or issues. Just idle with no throttle input. Annoying.
Member
Joined: Aug 2015
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From: Norton, Massachusetts
Mine 2005 S430 4Matic * Wife's 2005 S430 4Matic *
How many gas pedals have you tried? Was there only one replacement? Was it new or used?
You may have received a bad replacement pedal. Do you have your original pedal? Can you check the sensor on it and see if it is functioning with a multi meter? Can you check your replacement pedal and see if you're getting the same readings?
If it's possible that your replacement Throttle Body was bad 3 times, then maybe, could your replacement pedal also be defective.....possibly?
Like kraut56 mentioned....there's only 3 pieces to this issue. Throttle Position Sensor (gas pedal), Throttle Body or the wiring.
You may have received a bad replacement pedal. Do you have your original pedal? Can you check the sensor on it and see if it is functioning with a multi meter? Can you check your replacement pedal and see if you're getting the same readings?
If it's possible that your replacement Throttle Body was bad 3 times, then maybe, could your replacement pedal also be defective.....possibly?
Like kraut56 mentioned....there's only 3 pieces to this issue. Throttle Position Sensor (gas pedal), Throttle Body or the wiring.
Newbie
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From: CT
2000 s500 2006 s500
place in ct independent
Performance Imports, Danbury, CT they are a Mom and Pop business, can't go wrong with them. Johnny
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Mercedes
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S600 - 2003
Excellent. And thanks for the unexpected reply. I've seen your truck/trailer on 91 nearby before.... and I may have launched past you in the blown vette.
Apparently, the pedal and 3x TBs work perfectly. They had their master tech work on it this time and he went a little further than the initial guy on my prompting. The computer itself died and I have a replacement coming in from Benz for Thursday since they said it is essentially a proprietary part and install/program for the car. Not cheap, but still less than a new TB and/or a new TB and then adding a new ME on top of that expense.
Or, if wisdom on here negates the dealership's direction about it needing to be a custom piece and not from a donor S600, I am all ears if I can change it out without dealer expense.
Apparently, the pedal and 3x TBs work perfectly. They had their master tech work on it this time and he went a little further than the initial guy on my prompting. The computer itself died and I have a replacement coming in from Benz for Thursday since they said it is essentially a proprietary part and install/program for the car. Not cheap, but still less than a new TB and/or a new TB and then adding a new ME on top of that expense.
Or, if wisdom on here negates the dealership's direction about it needing to be a custom piece and not from a donor S600, I am all ears if I can change it out without dealer expense.
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From: Ball Ground, GA (N of Atlanta)
2003 S500 2007 GL450
While it is possible to change the ECU (assuming that is the computer that they are saying is bad), it isn't quite that simple.
The ECU, the transmission shifter, the ignition computer, and the key/keys are a matched set. It is often possible to buy a used theft-critical set and install it, but you will also then probably need to have the computer parameters set to match the equipment on your car. This has to be done using SDS (STAR Diagnostic System), either the $30 - $40,000 dealer system, or the $450 - $600 Chinese clone version that individuals buy. You might find an independent who has (and knows how to use) SDS. Or, if you are interested in DIY, you could buy an SDS clone. You can usually sell a proven, working SDS for pretty much what you paid for it - they don't depreciate much...
A dealer can purchase a "virgin" ECU and then match it to your car, and it sounds as if that is what is planned.
Good luck, regardless of the path chosen. And, we hope that it turns out to be a Happy New Year!
The ECU, the transmission shifter, the ignition computer, and the key/keys are a matched set. It is often possible to buy a used theft-critical set and install it, but you will also then probably need to have the computer parameters set to match the equipment on your car. This has to be done using SDS (STAR Diagnostic System), either the $30 - $40,000 dealer system, or the $450 - $600 Chinese clone version that individuals buy. You might find an independent who has (and knows how to use) SDS. Or, if you are interested in DIY, you could buy an SDS clone. You can usually sell a proven, working SDS for pretty much what you paid for it - they don't depreciate much...
A dealer can purchase a "virgin" ECU and then match it to your car, and it sounds as if that is what is planned.
Good luck, regardless of the path chosen. And, we hope that it turns out to be a Happy New Year!
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S600 - 2003
*** RESOLVED ***
For all the back and forth, the end result is that the engine management computer had died. A quick swap and the car is back on track.
I wanted to be sure to post the solution. You never know who will have the same or similar headache years down the road and come seeking answers on the forum.
Loving the car again, and just in time for winter to begin here.
For all the back and forth, the end result is that the engine management computer had died. A quick swap and the car is back on track.
I wanted to be sure to post the solution. You never know who will have the same or similar headache years down the road and come seeking answers on the forum.
Loving the car again, and just in time for winter to begin here.
