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Discussion Starter #1
i really wanted my first post to be a formal "hello" and "here's my new pride and joy" but my new m5 has started throwing codes and going into engine failsafe prog (35mph speed limit) before i could even get to that. i drove it ~430 miles home, from the "dealer", without and hiccup and then... i've done a good bit of searching (m5board.com and google) to no consequential avail. hoping you guys can forgive me for asking rather than giving on my first post! some codes to ponder and advise on as read directly off the tape that printed off of the local mechanic's diagnostic tool (kicking myself for not having a peake reader, yet!):

-"78 signal, throttle potentiometers 1 and 2 different"
-"76 signal, throttle potentiometer 1"
-"6B function, electric gas actuator: adaptation"

not familiar with any drive by wire stuff. any thoughts on what needs to be done and what i can do myself diagnostic/fix wise (wrenched 95% of the things on my e36 m3...fairly capable tools wise and experience wise) to remedy the situation? thanks, guys. lookin' forward to being a part of the forum. was a contributing member to m3forum.net for a good while and looking to do the same here.
 

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Discussion Starter #3
kind of what i've begin to deduce. guessing they're synonymous. especially since there are two. thanks!
 

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Lev,

I'm in Cary (work in Raleigh) and have a Peake reader if that will help at all.

Also - BMW CCA area meeting tomorrow (Thursday) in RTP. Maybe someone there lives closer to you and might have a reader.

I'd tend to agree with chowder and suggest that all codes are related to the same problem.
 

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Descriptions with the codes are everything. Don't throw out your #2 potentiometer it is still good. The 76 says that sensor 1 is no good. 78 is a secondary check that says 1 and 2 have different readings. You would expect that since 1 is not working 2 had best read different. The 6B is the precheck on the drive by wire system and if 1 is not good it will trigger. You are fixed and now you have a spare for later diagnosis if you need it.

There are some better descriptions for the codes from Peake.
View attachment Peake M5.xls I have another version printed on my desk I think it comes from BMW but I can't find the file on my computer I will post it when I find it.

Congrats on your success!
 

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Discussion Starter #7
wow-thanks! just what I was looking for. so just to make sure: throttle potentiometer = throttle position sensor?
 

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Probably #16 in this diagram

RealOEM.com   BMW E39 M5 Throttle Housing Assy


Search under throttle position sensor and you'll find some diy write ups.

I replaced both mine when I was doing a bunch of other stuff. They weren't pushing codes, but more along the line of they will probably fail at some point and I already had the car in pieces. Kind of a pain to get to and definately worth changing out the screws for hex bolts to hold them in.

Good luck
 

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Discussion Starter #10
ahh. so you have to replace the whole assembly...good to know. was coming up with nothing searching for throttle potentiometer/sensor.
 

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Discussion Starter #11
not looking like throttle position sensor/potentiometer is the same as the throttle housing assembly. hmmm. need a part # if possible so I can make the cut off for overnight delivery (at work)...
 

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Sorry, maybe I'm confusing the issue

I was talking about the throttle position sensor (part number 13637840383). There are two of them on the back of the engine. If you click on the link to realoem, they should be #15 in the picture (the diagram is labled throttle housing assembly, but that's kinda misleading). Since your are also getting the cross check code I was assuming that it was one of these sensors going bad, not the physical throttles themselves or the motor assembly that opens and closes them.

Perhaps one of the other guys can confirm that this is the likely cause and not something else.
 

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Discussion Starter #13 (Edited)
alright...so i'm gonna go ahead and replace both of them since i'm now getting codes that lead me to believe both of them are bad. any "while-you're-in-there" things i should check or replace while i have the intake box/plenum off? did everyone replace the associated gaskets when they did this (can only see one, main gasket that seals the top cover to the bottom part...any more?)? couldn't find any good DIYs in my searches--only talk of how much of a pain in the a55 it was to unscrew the phillips head screws that fasten the sensors in...i guess the online TIS is as good as it's gonna get? sure do wish there was a bentley manual for this m5 like there was for my e36 m3.
 

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Discussion Starter #14
got the parts in (2x TPS's, 4x "O" rings, 1x plenum cover profile gasket)...got her all opened up...will be finishing up tomorrow. i am confused, however, at the torquing sequence as outlined by the online TIS (again, is this as good as it gets for us as far as a technical service manual?). in the torquing down procedure, when it says "Tighten screws ① and then screws ② from inside to outside to preliminary torque of approx. 5 Nm." do they mean torque all of the inside screws of bank 1 and 2 to 5 Nm before even torquing down so much as 1 of the outside bolts of bank 1 and 2? i.e. torque down all the inside bolts then torque down all the outside bolts? annoying that the TIS is displaying those weird characters instead of the corresponding numbers. any guidance would be greatly appreciated!
 
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