e46 318i potentiometer error

[eller]

e46 318i m43 1998 (cable) throttle.

cars is in limp mode ( drives normal )

milage meter acting up a bit somestimes

119 potentio meter
115 coolant sensor
135 knock sensor


getting a 3v refference on the blue wire going to the potentiometer (unconected from the tps)

i've read that its supossed to be 5v, but not sure if that aplies to this model.

when i connect my multimeter it read 2.3v at Potentiometer (conected) and moves down to 1,5v as i open the throttle.

i cant even read potentiometer voltage in INPA, it reads 0.00v.

heres some interesting data i found.

From 1999 to about 2002, BMW had a hell of a time, chasing throttle issues. Back then, the progression was this:
1) clean the TB (almost never worked)
(2) replace the TB (an ~85% fix)
(3) replace DME (10%)
(4) replace wiring harness.




HELP.

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i've tried buying a used TB from 2001 on ebay, no changes.

[bmwdirtracer]

Jeez, I recognize that quote....I wrote it.

We've never had a 4 cylinder E46 here, but the principles are the same.

IF you truly have 3 volts going to the throttle position sensor, that is problem #1. Yes, it absolutely needs to be 5 volts. I would have to suggest looking up the wiring diagrams for your car, and testing the continuity of the wires from the DME to the TPS. While you've got the DME unplugged, use some electrical contact cleaner to clean both sides of the connection, at the DME and the TPS. It may be that your DME has gotten wet, and some of the pins may have some corrosion.

Wiring diagrams for your car:

https://www.newtis.info/tisv2/a/en/


I haven't tried to look up your car on TIS. We didn't have the M43, I don't believe, just the M42 and 44. From a quick search of these, the throttle body was a purely mechanical unit, no throttle motor, and the only potentiometer would be the Throttle Position Sensor, which bolts to the side of the throttle body.

[eller]

heres what i do.

ignition on.

1.i put on lead from the multimeter on the batteri +.

2. then i unplug the two wired connector from the tps. theres a Green wire which i strongly belive is ground, and a blue wire that goes to the dme.

i then put the other lead from the multimeter in the connecter(unplugged from the tps) to the blue wire. and it says that theres 3v present. Okay!

then i plugged the tps connecter back into the tps, on lead on batter+ and the other lead i stuck in the potentio meter blue wire connecter.

with tps connected, and ofc ignition on. the multimeter reads 2.3v. and drops to 1,7v when i open the throttle by hand to fully open.

Is the dme bad and sending only 3v.??

i also removed the female pin on the blue wire that goes into the dme to tighnt it up a bit( it seemed loose.) didnt help
then i made a small cut in the blue wire close to the dme and stuck my multimeter lead in there and it said 2.3v. so i dont think its the wiring.

i seems like a dme fault to me ?

[bmwdirtracer]

Um, we have a problem; actually, a couple of them. Please don't take this wrong, but I think you need to take your car to a mechanic.

1) You don't hook a multimeter to the + positive side of the battery to test voltage on a wire. You hook the black wire of the multimeter to any good ground, and the red wire of the multimeter checks the wire for voltage.
2) You do NOT cut wires to test voltage. Exactly how are you planning to restore that wire?
3) The TPS has THREE wires, not 2. These wires are Brown/Black, Brown/Violet, and Green/White, according to TIS:
https://www.newtis.info/tisv2/a/en/e...ometer/q3KGQrF
It is possible that I've pulled up the wrong year 318i E46 M43, but a TPS must have three wires: power, ground, and signal.
I'd mention that these wire colors are also exactly the same as an E36 318 M44, U.S. version, so it's VERY likely these wire colors remain the same, year to year.
4)Removing pins from the DME connectors is best left to a pro with de-pinning tools.

Whatever blue wire you tested actually has 9volts, by the way, because your method would actually give you a voltage drop test. With a quick check, I can't find any 2-pin connector with a blue wire and a green one.

My guess is that your wiring harness is incorrectly connected. This might well explain your codes, and the fact that INPA is reading zero for the TPS.

[bjornk]

Um, we have a problem; actually, a couple of them. Please don't take this wrong, but I think you need to take your car to a mechanic.

1) You don't hook a multimeter to the + positive side of the battery to test voltage on a wire. You hook the black wire of the multimeter to any good ground, and the red wire of the multimeter checks the wire for voltage.
2) You do NOT cut wires to test voltage. Exactly how are you planning to restore that wire?
3) The TPS has THREE wires, not 2. These wires are Brown/Black, Brown/Violet, and Green/White, according to TIS:
https://www.newtis.info/tisv2/a/en/e...ometer/q3KGQrF
It is possible that I've pulled up the wrong year 318i E46 M43, but a TPS must have three wires: power, ground, and signal.
I'd mention that these wire colors are also exactly the same as an E36 318 M44, U.S. version, so it's VERY likely these wire colors remain the same, year to year.
4)Removing pins from the DME connectors is best left to a pro with de-pinning tools.

Whatever blue wire you tested actually has 9volts, by the way, because your method would actually give you a voltage drop test. With a quick check, I can't find any 2-pin connector with a blue wire and a green one.

My guess is that your wiring harness is incorrectly connected. This might well explain your codes, and the fact that INPA is reading zero for the TPS.

Dirtracer,

A local Indy I called who was a fomer tech for over a decade before opening his shop said very few shops are replacing pins they just replace the harness. Is that your experience? I looked up all the pin tools that go with the connectors crimping tools etc, I’d love to see someone using these


Eller,
I suck at multimeters. But have been using scannerdanners you tube channel and schrodingers box as resources...it’s helped to try to perform some simple exercises before trying to actually diagnose stuff. Maybe you just wrote up what you did wrong... take a deep breath.this stuff sucks when you need your vehicle,lots of bad information out there reader beware.....


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[eller]

so theres 9 volt going to the pontenti meter, and the green must be ground. i traced the green wire from the tps to the dme box where its connected with two other green wires( one coming from i oil level sensor i belive.) and the other going into the dash area where i cant see. maby on chassis for ground.

does this sound correct

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shouldnt there be 5v not 9 ?

[bmwdirtracer]

No, that is not correct. The TPS / potentiometer has three wires, not 2. Your wire colors are all wrong anyway. Please read what I wrote above, and look at the wiring diagram which I provided you. You are testing the wrong plug.

Furthermore, all THREE wires for the TPS go to the DME itself, not just the DME box. None of them meet with any other wires. You are testing the wrong plug, and your TPS isn't working because you have the wrong plug attached.

[eller]

i think we're on to something here, for some reason the wire colors dosent match the TIS ones. Very strange.

i think someone has messed with the car wiring before me, i've had these faults ever since i bought the car.

[eller]

this is strange, i belive like you said that theres supossed to be 3 wires going to the potentiometer.(i only got two wires)and no sign of a third wire ever being there. Why else would there be 3 pins on the potentiometer. then the 3 pin just does nothing.

im starting to belive someone changed the wireing harness or something before i bought the car.

I gonna buy new engine harness



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[eller]

Okay i think we solved this.
__________________________________________________ ____________________i





i belive that when i found car on this used cars site, it said something like this: 279.000km, with new engine. (but no documentation on this, so therefore the low price..

= the engine has been replaced and wire harness hasnt.

[eller]

[eller]

SOLVED: The plugs was indeed not connectet correctly. The plug for the potentimeter was on the generator. and the one from the generator was on the potentimeter. they have same plug so the can easyli be switched around.

Thx for helping, i've spent months scratching my head.

i was finaly able to delete the 119 error and see the potentimeter voltage in INPA.

I am happy but at the same time madbecause i didnt notice this before that the plugs had been switched around by previous owner.

thanks (Bmwdirtracer)

[bmwdirtracer]

You're welcome.

Don't be mad, be glad. The answer is right there in the wiring diagrams. Become familiar with these, and it will benefit you in the future.

All the best!

[bmwdirtracer]

And now that we've solved the riddle of the 2-pin TPS,


bjornk:

No, I don't replace wiring harnesses because a pin or two is bad. If it's a small plug (half a dozen wires or less), I might cut the plug off a parts car, and splice the wires (CORRECTLY!) Or, I'll de-pin the plug, if it's one or two wires.

De-pinning is actually becoming easier these days, as BMW has started putting plastic "locks" on the plugs, to hold the pins in place. Quite often, I can now remove the lock, then use a tiny screwdriver to press the tab on the pin to remove it. I have a collection of BMW and Bosch pins and connectors, and I am very confident in my wiring skills.

Now, if someone hooks a normal 5-pin relay into the circuit of an E36 secondary air pump, then yes, we're probably going to need a new wiring harness, because that lets all the smoke out of the wires, permanently.

[bjornk]

Eller,
Glad you figured it out... a swap.....

Bmwdirtracer,

Not trying to hijack a post but guess there’s a big difference between the diff connectors and what they are going to and carrying. Maybe harder to reopen the dme connector than a fan or edkmdk connector.

You’d think the engineers wouldn’t leave two connectors in reach of each other that could be easily swapped...how hard is it to put a different color or shape
Connector there?

I have a list of connectors and trying to cross reference it with tools. Been researching threads to find the best tool out there that would hit the most connectors on my e 39, most the posts on this topic are old but I guess there’s no reason to update if there aren’t new tools on the market .

I’ve taken a few apart with a screwdriver but I think I need a tool....especially if I were re crimping terminals...

I think I’m developing a phobia of connectors ....




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[bmwdirtracer]

I guess the engineers figured that we could count pins, or read wire colors from the wiring diagrams, or even label the connectors when we disconnect them.

[bjornk]

Yeah.....if it’s your day job. After a few drinks in a dimly lit carport on a weekend.....they need to think of that variable ..

Throw in some frustration cuz you need the car. You see a little of people on here losing their $$$.

But yes, I hear you..follow the instructions...read them before taking things apart.

I always label and photo .....


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[bmwdirtracer]

Let's acknowledge that BMW factory engineers do not want people working on their own cars. If you re-read the above story, I'm sure you'll understand why they feel that way.

[bjornk]

The people will prevail!

( sometimes)

We are definitely living in a changed time ( Information Age). While these forums are a tremendous help, often exceeding any manual , there’s a ton of misinformation out there. And the learning process is slow and cAn be costly . I saw a post recently where a guy was saying he uses dialectic grease to improve conductivity ... I mean these sites have to be valuable and yet they take resources to run.

I appreciate those of you out there providing clarity


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