cal1

My SL has been sitting in the garage for nearly six months with a trickle charge on it. It was sunny and 65 in Southwestern Wisconsin today so I figured it was time to break it out. After bringing her up to normal engine temp, I smashed the throttle and the torque produced that shiit eating grin I haven't experienced in months. After slowing down, I tried a kick down and got nothing. I slowed and then realized the car was in limp mode. After shutting down the car, limp mode came back one more time. 1/2 hour later, the car was back to its normal self. I drove it for about an hour stopping and starting a number of times. No more trouble.

The car threw a P0123 code which apparently relates to the throttle positioning sensor. My question is which one? Isn't there a sensor on the accelerator pedal and another sensor on the throttle body? In spite of the trickle charge, I got the electric consumers offline warning and even a warning that ESP was offline. Could the fault have been related to ESP being offline? Once it came back on, I had no trouble even when I manually turned it off.

I am still giddy from the spirited drive in the SL. Even after all these years it stirs emotions like crazy. That visceral grunt from the massive torque produced by the SC is awesome. First day with the car out of the garage in six months and I have already told it "I hate you" and "I love you " a dozen times. Damned cars .

cal1

Quick update. I drove the car this evening. 50 degrees and the SC was loving it. The CEL cleared itself and the little SL is pulling like a freight train.

Georgee6086

The exact same thing happened to me last week, car was sitting for about a month prior. I just did the tb reset with the gas pedal and all is good.

alx

"Esp off" means generally weak battery. When that happens many other strange things happen as you have noticed. Driving around charged the battery and things are back to normal.

But... Those cars don't like to sit. That is when they develop problems. Just sayin...

cal1

No more problems since? I should do the sneaky reset myself, although I was on the freeway on Saturday going about sixty and did a kick down. I got that familiar feeling of just having been rear ended by a semi immediately followed by rapid acceleration.

This is the first time I have had a low trunk battery. Not sure if my trickle charger was not working or if it is time to replace the battery. I do notice that even if the ELM is off, it seems to drain battery power.

Your right of course. We had an incredible run of below freezing days in a row this winter. I run high performance summer tires (Nittos) on the SL. They are scary in cold weather. I typically get a change to break out the SL during the rare 50 degree days in the middle of winter. No such days this winter.

rsr911

I have had this issue. The detent swith in the accel. pedal assembly - it went bad. Had full power until you go to max throttle then limp mode. Check the accel. pedal. FYI

Georgee6086

No problems since the reset, on a side note I think that either the battery was the cause or maybe from just starting to car in the garage so many times thru ought the winter and not hitting the throttle. Before the winter my trunk battery was pooched and I got p0123 3 or 4 times. I changed the battery over the winter but didn't really drive the car since ( a few trips around the block but never smashed the gas pedal) since last week after the tb reset I've clocked around 1200 miles and everything is GREAT! Except my wallet gas prices are thru the roof over here and I can't drive like a normal human. I just bought the car in November 2013 and havent got a chance to really enjoy it until now and all I have to say is WOW, the tq is unreal

cal1

Thanks, I will check that out. It sounds about right because I had good throttle response until I went WOT. That caused limp mode.

I find myself driving the same way

cal1

Well I guess the SL55 gods were just angry at me for not running the SL for so long. Ever since the first code issue things have been fine. The trunk battery is back up to power and all is well.

Got close to sixty today. By the time I had the SL on the road, it had cooled to high forties, but there was still some heat in the pavement. I was rolling at about fifty when I was losing my lane up ahead. A couple kids in a WRX were next to me. I swear they were just hoping I would light it up. Not one to disappoint, I went WOT. Nothing like breaking tires loose at 50+. The SC was clearly loving the cool air. Got a big from the kids in the WRX.

Georgee6086

Niceeee!!! Breaking tires loose at 50 has got to be a good feeling knowing everything is working good. I have a question for you ( cal1) I noticed your time on Dragtimes and was wondering if you had any pointers for me as I hope to ge going to the track next weekend. I've never been yet in this car. What were your mods at that time? I've been talking smack to a few of my buddy's over the winter and hope to break into the 11's. The track we usually run at has next to no track prep.

cal1

Looking at your mods and the tires you are running, I am guessing you are only one good launch away from breaking into the 11s. When I ran that 11.86 that you saw, my mods were about the same as now. The tires were Toyo T1Rs.

My setup for the run: lowered tire pressure to about 25 lbs., ESP off, raised car height to max. Backed into the water and heated the tires with a burn out. Launched from idle. Dialed on throttle deliberately, but not just a tromp. Maybe 1 to 1.5 seconds elapsed between no throttle and full.

It seems launch techniques are a personal thing. Everyone has a different technique and many get good results. Most people will tell you not to smoke any tire other than a true drag tire or a street legal drag tire. What they do instead is a quick spin of the tire just to clean off any debris. That is all I ever did before until some drag track rat that was helping me told me to lower the tire pressure and heat them up. Results speak for themselves, my 60 ft time of 1.76 was the best I ever accomplished. From what I understand, it is a good 60 ft time for street tires. You should be able to heat up those R888s and stick nice.

Some of the W211 guys drag in dyno mode. I have never done this. The track that I frequent the most has a corn field at the end of it and there are always tire tracks in the field from someone who could not stop. Dyno mode means ABS disabled too. I like knowing I can stand on the brakes and stop at the end of the run.

A couple final thoughts. Some guys on the boards basically do a smash and go. If they stick they stick. If you can pick your weekend based on good low or even negative density altitude, do it. I'm thinking a cool spring evening where there was some heat during the day and the track temp is warmer than the air temp. Many of URnexts best runs were done at Sacramento on a dry cool winter day with negative DAs. Perfect SC weather. A number of guys I know throw bags of ice on their SCs between runs. I never did it. Always made me a bit nervous.

Good luck, I look forward to hearing about the runs. I won't be too upset if you knock me down the list at dragtimes.

Georgee6086

Thank you soo much for your advice, I really appreciate it. I was out on Saturday practicing my launching in the industrial area near my house and think I got a good decent handle on it. One thing that I noticed is when I raise it to highest setting I seem to get a little wheel hop. (i am lowered on links) I guess there's no substitute for practicing at the track as the surface will influence the traction. It's a 2.5 hr drive for me to the track and I'll be lucky to get in 2 runs but I'm dying to find out what it will do. On a side note I was on the hwy on my way to pick up my gf and low and behold a black BMW m5 v10 flys by me. So of course I had to catch up to him, sure enough we find ourselves side by side at around 60-65mph with a clear stretch ahead. After about 10 seconds of side by side I hear his exhaust and his front fender raise about 2 inces so I nail it, I must have pulled at least 5-7 cars on him so I let off around 125mph and tap the brake, he dosent stop and flys by me. I was soo happy for the rest of the day that was my first go with someone in this car. I'm still gunning to break into the 11's but I know what its like at the track and I'm no stranger to disappointment and the long miserable drive home. (big reason why I jumped ship to automatic from a stick)

mcguirja

Cool

Which part of the GTA are you in? I've practiced launches out in some west end industrial parks. They're generally very quiet on weekends, so a great place to practice.

Georgee6086

I'm in Pickering down by the beach. That's a beautiful sl63 you have I love the white.

cal1

You're welcome. I love the fact that you want to run your SL at the track. There aren't that many of us that do. To me, it is just one more great thing about the car. You can cruise to the track in comfort possibly with the top down, knock out some very respectable low 12s or 11s, and later on meet the wife or significant other at a fine restaurant where there is a good chance the valets will agree to leave the car out front (slip them a twenty, it always works for me).

Not sure what is up with the wheel hop. I also wonder how much difference raising the car really does especially considering ABC should be keeping the car's weight balanced. Practice is truly your key although launching on the street can be very different from a drag strip depending upon prep as you well know.

Love reading about the encounter with the M5. Some of those "M" guys seem to think they are invincible. I had the pleasure of dispatching a noisy M3 a few years back. The funny thing was, he did just like the M5 guy you walked. Most people that I have had runs with pull up next to me and give me thumbs up instead of screaming off with tail between legs.

I'm looking forward to reading about how your track day goes.

Georgee6086

Forgive me I am new on this forum and can't figure out how to add a quote to my post, or attach pic on profile for that matter.
Cal1 I agree 100% about the SL it is an overall wonderful car, it's a hwy monster, extremely comfortable, looks are top notch, and holds its own at the drag strip. Then to top it off the roof folds back at the push of a button and gives the car a completely different look and feel behind the wheel.
I would think raising the car to highest setting during a launch would be the best way to get a larger contact patch but who knows.
The group of friends I usually go with run old muscle cars and they typically run between 11.50 to 12.0's they would be shocked to see a 4500lb car infront of them at the 1000 ft mark.

cal1

Click this

located in the lower right corner of the post you wish the respond to. The complete post will show up in the text box for you to respond to. You can edit the quoted post like how I removed all of your message except for the first sentence.

Robert Newhook

What is the name of the detent switch? I can't seem to find it in my searches. Is it part of the pedal assembly? Can it be purchased separately?
How do you know if it's the detent switch or the pedal position sensor? My car is fine until you go full throttle - then slow throttle response until I restart the engine. But it's throwing a P0123 Throttle position sensor code.
Any help is appreciated

bobterry99

The only switch related to the throttle pedal assembly is the kickdown switch.

Code P0123 relates to a voltage signal from the pedal and does not involve the kickdown switch. You may be able to cure the problem easily as I was able to do as described here: https://mbworld.org/forums/sl-class-...ml#post7848332. Without a diagnostic tool which displays the pedal voltages that procedure could be quite tedious. Alternatively, I suggest buying a replacement pedal assembly.

Mercedes' description of code P0123 mentions "potentiometer", and this is an electro-mechanical component subject to wear and tear. With such components I think it's generally best to replace with new. However, I saw something recently which indicated there are in fact no potentiometers in the R230's pedal, and if this is the case, then I would be inclined to purchase used.