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Discussion Starter · #1 ·
Hey fanatics,

kburger once again. 732,000 miles on 2000 323ci. I owe that to this forum and a lot of you. Thanks! Down again for throttle body/ICV issues again. Our cars were designed right between throttle cable and drive by wire. So we have a hybrid over engineered monstrosity that costs 700-1000 dollars new. 10 wires connect it to ecu. Insanity.Extremely sensitive to millivolts can't even solder a new connector on engine harness. Looks like the refurbs on ebay are garbage I think they come from China. Maybe I'll try to dissect one and try to fix the electronics inside. Has anyone attempted this? Thanks
Kburger.
 

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Glad to see your car still up and running. I can't help with your problem, but wish you the best.

Sent from my SM-N960U using Tapatalk
 

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Discussion Starter · #3 ·
Lol thanks. Plenty of help here if I really need it. Just want to know if anyone dissected the monstrosity hybrid throttle body thanks
Kburger
 

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2002 330 Ci
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Sorry for my ignorance.... is your setup different from an 02 m54b30? You mention hybrid cable and drive by wire. Mine is all drive by wire.
 

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2004 325i automagic
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Sorry for my ignorance.... is your setup different from an 02 m54b30? You mention hybrid cable and drive by wire. Mine is all drive by wire.
Yes, from what I understand the early ones have a cable from the pedal to the throttle body that attaches to a potentiometer that then converts the mechanical throttle input into an electrical signal transmitted by wire to the electronic throttle actuator ... or something along those lines ... it's kinda nuts ...
 

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2016 340i xD 6-spd
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You wouldn't be having an issue with the round two-stage connector down there, would you? First time I did it, thought I had it right, but it wasn't. ...and of course an electrical cleaning spray wouldn't hurt.

I'm sure it's not this, but just in case.

...and a bump. Got to save the granddad of e46s!
 

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I think I mentioned this before. But if Kburger is having repeated problems with his M52TU throttle body (used only in '99 & '00), and has already tried replacing it with a replacement, it is likely not his throttle body, but the wiring in the stupid round 10-pin connector on the harness. The back of that connector, and its pins/wirings is open to the elements in the air flow around the engine block and easily degrades, causing tiny changes in millivolts sent/received between DME and throttle body (aka MDK), throwing the car into limp mode.

I have replaced the throttle body on my M52TU e39 six or seven times.

Here is a solution:

You could also try a used engine harness, but it will soon have the same problem. Several years ago, I looked into a new Genuine harness...according to my dealer parts counter, it had to be ordered from Germany and it was $750.

I haven't fixed my car yet..its in storage, but one idea I have, is to get the parts referred to in the link above, find a used harness - make sure its the correct one..year/model/trans, have the repair done professionally by an electronics specialist (I suck at wiring/soldering) and replace the harness. This will minimize down time.
 

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Discussion Starter · #9 ·
Excellent intelligent replies thank you all. Cleaning the sh** out of the round connector my codes then shifted to icv. After pulling the boot about 10 times, no exaggeration it finally tore at the ICV ring clamp. It was original guess I can't complain. Cleaned ICV wasn't that dirty. Clacked nicely, still ICV errors. Lubed with Wurth HH plus. Best lubricant for anything BTW. I didn't want to lube it but running out of ideas. New icv and boot coming today. Codes are icv mechanical fault. ICV air leak. Will update what I find. I have another thread for heater bypass hose I think that one is my ihka head unit. Always working on this car. Thanks

kburger
 

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Discussion Starter · #10 ·
Excellent intelligent replies thank you all. Cleaning the sh** out of the round connector my codes then shifted to icv. After pulling the boot about 10 times, no exaggeration it finally tore at the ICV ring clamp. It was original guess I can't complain. Cleaned ICV wasn't that dirty. Clacked nicely, still ICV errors. Lubed with Wurth HH plus. Best lubricant for anything BTW. I didn't want to lube it but running out of ideas. New icv and boot coming today. Codes are icv mechanical fault. ICV air leak. Will update what I find. I have another thread for heater bypass hose I think that one is my ihka head unit. Always working on this car. Thanks

kburger
Sorry. How come in my profile I cannot find my own threads ? I think I saw a bump. In my
 

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Discussion Starter · #11 ·
Very frustrated with editing messages sorry. On topic to me a potentiometer, or pot, varies current as you spin a knob. Many variations in that of course. So, all those wires on the TB, are they basically positions on a pot? As the TB rotates with the cable it hits each position on the pot which activates each wire, just a high/low voltage?
 

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2004 330Ci 115k miles
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…to me a potentiometer, or pot, varies current as you spin a knob. Many variations in that of course. So, all those wires on the TB, are they basically positions on a pot? As the TB rotates with the cable it hits each position on the pot which activates each wire, just a high/low voltage?
Download this document, then start reading on page 11.

Throttle valve wiring diagram.
 

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Discussion Starter · #14 ·
Download this document, then start reading on page 11.

Throttle valve wiring diagram.
Excellent I shall do that. Installed original TB back in car. Clean the heck out of ICV and lube with wurth HH plus. Yes I understand the problems with lube it attracts dirt. Fixed heater bypass valve had to install original IHKA controller replaced it with new style cus the tiny fans inside always break. New style ihka must not be compatible with my car. So everything working great now let's see how long it lasts. I have new parts coming today for everything including torn boot I glued back together. Thanks all for help. I have so many parts for the car because I fix it without parts. I'm buying another used throttle body. When you find the right supplier they are pretty good used with a low mileage donor car.
kburger
 

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Discussion Starter · #15 ·
Drove for several miles. Sitting at idle went into limp mode again. Codes only point to throttle body. Of course. Gonna replace ICV hopefully gets here soon.
 

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Discussion Starter · #17 ·
Agreed. Pretty sure I already have that wiring diagram of the TB in my Bentley manual. Would love someone to explain to me what each of the 10 wires is doing. Is each wire part of the potentiometer? Does the voltage vary on each wire or is it just on/off high low?
Kburger
 

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Discussion Starter · #18 ·
Throttle body output stage cutoff after diagnostic error. What exactly is the output stage and what is the diagnostic that is failing ?
 

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Agreed. Pretty sure I already have that wiring diagram of the TB in my Bentley manual. Would love someone to explain to me what each of the 10 wires is doing. Is each wire part of the potentiometer? Does the voltage vary on each wire or is it just on/off high low?
Kburger
Engine throttle
With the aid of the actuator of the throttle valve, the throttle valve can be opened independently of the accelerator pedal position.
The motor throttle valve in the M52 and MS42 differs from electronic engine management (EML) in the following points:
-No potentiometer on accelerator pedal but rather a double potentiometer on the pulley of the motor-driven throttle valve
-There is a Bowden cable fitted between the accelerator pedal and motor-driven throttle valve which is also used for emergency operation purposes.
Deleting adaptations on completion of repair (M52):
The adaptations should generally not be deleted on completion of repairs (parts replacement). After replacing the throttle valve (MDK) the adaptation values should be deleted in order to avoid a fault code entry.
 

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Discussion Starter · #20 ·
Engine throttle
With the aid of the actuator of the throttle valve, the throttle valve can be opened independently of the accelerator pedal position.
The motor throttle valve in the M52 and MS42 differs from electronic engine management (EML) in the following points:
-No potentiometer on accelerator pedal but rather a double potentiometer on the pulley of the motor-driven throttle valve
-There is a Bowden cable fitted between the accelerator pedal and motor-driven throttle valve which is also used for emergency operation purposes.
Deleting adaptations on completion of repair (M52):
The adaptations should generally not be deleted on completion of repairs (parts replacement). After replacing the throttle valve (MDK) the adaptation values should be deleted in order to avoid a fault code entry.
Thank you mrmcar you are very knowledgeable. I got a new Intake boot. The one with hose for ICV. Had to walk away the crazy part is people think I should be enjoying this. Sucks soooopoo bad. I'll keep posting getting POT errors on solenoid 1 and 2 for TB. Replaced TB used from a trusted local seller drove hour and half to pick it up. Will see what happens.
 
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