oakcreekeric

Hello All -

I tried to do some searching, but this is a difficult one to explain, hopefully someone will make sense of what I'm trying to say/explain -

I was driving my 03 SL500 and I "got on" the accelerator rather aggressively - it was need for a short burst of speed and then I let off the gas. Now this is where the strangeness occurred - after letting off the gas, I had no pedal (no increase in RPM/speed) - nothing - the engine was running (I was coasting while in drive) and everything seemed fine, but when I tried to accelerate, I got nothing, I even pushed the gas pedal to the floor - again, nothing. I eventually pulled to the side of the road and put it into park and did a shut-off/restart - once I did that, I the had pedal response and I could rev-up up the engine.

What the heck is going on ???

kbob999

Common electronic throttle pedal not responding, or giving 'implausible' results, which puts car in limp mode.

Shutting off car will solve the issue. Punching it when running will create it again. If you go easy, it will stay away for a while.

Replacing the electronic throttle pedal (1 bolt and 1 connector) will solve the issue. This is a Mercedes 'feature' that you get to enjoy

oakcreekeric

So... doing a bit of looking - I have to replace the whole pedal ??

https://www.fcpeuro.com/products/mer...vne-2043000200

This is a first - but if this fixes the problem, it will make me happier, just lighter in the wallet

kbob999

Yes, you do.

See the little box on the side with the white trim ring? That is the potentiometer, that has a bad connection or bad mojo.
I've torn mine apart to see if it is DIY repairable...unfortunately it is not.

To confirm this part is bad you need to run a test using the SDS computer. But 99% of the time it is the pedal.

I think you need to spend a little more and get this part: https://www.fcpeuro.com/products/mer...ule-2303000004
Or one specifically for your car.
That is still a good price for a new Mercedes part. They go for $100 used, and have no guarantee.

Let us know if you get results, and what fixed it.

oakcreekeric

Thanks - I was using the link for reference - thanks for posting the correct one, saves me a bit of time.

I'll TRY to remember to come back and update the thread - Unfortunately, I live in WI and I won't see my car for another few months - This will definitely be one of my first priorities once out of hibernation.
Now, if I could only find conclusive information about wheels/rims and the correct offset for my year (03 SL500) - I have stock 17', but wanna upgrade to staggered 18" and I cannot find definitive information on what will work and won't work -

MikeJ65

Since it is 'throttle by wire', there are a number of checks to insure that it doesn't run away. The accelerator pedal has two channels which are each checked for high/low voltage limits and also cross checked to insure that they are calling for the same throttle position. It appears that most of the issues seen are related to over voltage on one of the channels at full throttle. While a new accelerator should fix the problem, you can also shim the pedal to slightly limit travel. This is easier to do if you can monitor voltage with DAS or another diagnostic system, but you can also use trial and error.

Also, be aware that the early '03's up to chassis 26959 used a different pedal (230 300 00 04) than the later ones (230 300 01 04). The early version has an actual kickdown switch to signal full throttle, later ones apparently just used potentiometer readings. There is a plunger that provides some increased resistance at full throttle, but it has no function other than feel.

oakcreekeric

My VIN # is WDBSK75F23F028293 - I'm guessing the last six (6) is the chassis number - 028293 - is it safe to say I have one of the later ones ?

kbob999

Yes - You have after chassis 26959, so you need the 'later' part.

We all learn from each other if a part fixes an issue, so do your best to help the community. We appreciate it.

Good luck after the thaw!

oakcreekeric

This seems to be a decent deal - looks like an OEM part

ml320x5

I am for that idea. We all here to learn from each other!
Some people were here to ask for help. Others give thought, suggestion and at the end, you won't hear anything back. People spent time to answer and I hope whoever raised the question should spend some time to get us feed back as well so we all could learn from it.

danmm7

This is a very timely discussion. My 2003 SL55 AMG has the exact opposite problem.
If I am on the freeway and I floor the car, it accelerates great, but once I let off the gas pedal, the transmission continues to stay in low gear (does not up shift), as if I am still flooring the car. Eventually, after a few seconds, the transmission will UP shift and the rpm will go down.
The rest of the time, under normal driving, the transmission shift perfectly fine. No delays in up shift or downshift. This issue happens only under full throttle, "pedal to the metal" situation.

I haven't scanned my car for any codes yet, but this behavior points to a faulty switch under the gas pedal. Am I missing something? What else could be causing this?
If it's the switch, based on this discussion, i need to replace the entire pedal assembly, correct?

Thanks!

BenzNinja

iTrader: (4)

first thing to do is reset upshift and downshift adaptation in Xentry/Das
then test again

kbob999

Interesting that I have the exact same car, and the exact same issue. I don't believe it is throttle pedal related.
I thought this was something in the shift programming that allowed AMG to hold a gear for engine braking, or a short throttle lift.
Might be time to experiment and start a new thread for this issue.

danmm7

I actually observed this right after i did adaptation reset (using key/pedal sequence, not my Star SW).
After the reset, the transmission shifts very smooth and proper, but the full throtle test on the freeway was not great. It kept the lower gear for awhile until it agreed to downshift.
Starting to wonder if this is even a defect, or expected behavior with these cars.

*** I just talked to the shop who tuned my car, including my transmission.... and they said that this is normal behavior with these cars at high speed, full throtle.

BenzNinja

iTrader: (4)

yes, possible
remember that after resetting adaptation you have to relearn adaptation first
driving strong is not good
reset > drive slowly passing all gears for a few miles
then medium for 10 min
then strong 5-10 minutes

whole safety learning is about 25 min driving

so if you didn't do this start over again

adaptation refinement will learn after that with daily drive

all this is to eliminate the corrupt adaptation factor

Ohmann

When my pedal went haywire Somewhere I read about the mass air flow sensor can cause hesitation in acceleration. I replaced it and allis well. It’s at the very rear of the engine between motor and firewall. 2003 SL500 120k miles. On the 12th driving it from Va Beach to St Petersburg yearly run to Florida. Can’t Wait

45turns

Well this is timely, just had the same issue in my SL55. Driving on the Highway, went to give it a little punch to pass a truck and NOTHING, works fine after a restart. Does anyone know if it throws a code when the pedal starts going? I've got an MBII but not the Xentry software.

MikeJ65

In DAS I think it is one of P20DC, P20DD, P20DE, or P20DF. DAS also gives alternate numbers, I'm guessing that these are the generic codes: P0122, P0123, P0222, P0223. The pedal has two independent circuits that are cross checked for redundancy, so the error can be in either circuit.

tonylinc

I had the issue where car runs fine till you floor the gas pedal. The ECU gets a weird signal if the throttle potentiometer is bad, and goes to confused mode. Happened a few times. Shut off engine, restart, all good again. Bought a replacement pedal assembly, easy to remove and replace, all good after that. Part cost a little over $100