c101 and x20 wire diagram (e30 M50 adapter)

[EtaSport]

If you have the etm you need to start on the "power distribution" page and go from there. Page by page you will find all the pins and wire colors. A more detailed list of where you'll find them, power distribution, starter, charging, fuel injection, fuse details, instrument cluster, and active check panel. There isnt a chart like the one above.

[cahomey]

I realized that a little after that post.

Eureka! I've discovered the secret!

[EtaSport]

So, I've found a little more discrepencies as my latest pin chart proved to have some errors.

Most of the stuff in the tabled diagram I found to be correct.

Pin 19 of the x20 is definitely SI reset function (Pin 7 of diagnostic connector)
so it goes to pin 11 of c101.

Pin 16 still somehow goes to the diagnostic connector. The function I found was that it was for SRS, however I believe that Pin 16 and 17 of x20 are for RXD and TXD diagnosis lines.

From what I gather TXD looks for errors in components and sends codes to the diagnostic connector. I was thinking maybe run Pin 17 (TXD) to pin 16 or the c101.

I was unable to get my code reader to work with the last diagram I came up with.
Here is my new list.
1-25
2
3x
4-12
5-23
6-22
7-21
8-24
9-20
10
11-19
12-8
13-13
14-14
15-15
16-17
17x
18-18
19x
20-abs.

[Mike B.]

Does your code reader work with this diagram??

[EtaSport]

Havent tried it yet, as I just came up with it. Something still bothers me about e30 pin 16 though.

It worked using addissimo's chart, but I traced the ETM thoroughly and m50 pin 19 is definitely SI reset. The only descriptions I found for m50 pin 16 and 17 were TXD and RXD. The e30 uses these but they come right off the DME and go to the diagnostic connector. Probably wont get a chance to check it out til this weekend.

[Jason89i]

Havent tried it yet, as I just came up with it. Something still bothers me about e30 pin 16 though..

its really encouraging to see others diving into the wiring diagrams. i hope you dont get too many emails / pms from people wanting to diagnose their wiring problems.

double check your e30 pin16 (wht/blk).

also, here's a hint. e36 m50 does not use pin16 (wht/yel) or pin10 (blu/yel) but.....the e34 does.

cheers, jason

[EtaSport]

Okay, so e30 pin 16 has to be not used. Since the 89 and earlier did not have airbags, then there is no way it should be hooked to anything im gathering. I assume its only purpose is to aid in a pinout test through the diagnostic connector on cars so equipped.

And I know e36 pin 10 cant be used, but it would match up for oil level, pin 16 I wasnt aware, but gonna have to go with the other oil level. So that leaves me with e36 pin 17. And im just a tad bit confused still. I cant figure why the code reader wouldnt work, it worked fine on my car.

[e30_kid89]

man im in for such a good time when it comes time for the wiring

e34 harness + 91' 318iS body/harness =

so you said the ETM you got ETAsport doesnt really cover the 318iS in depth??

[EtaSport]

318 is in the ETM. It has everything from 84 to 92, 318, 325e, 325i, 318i, m3, 325ix, and 325ic.

The discs with the e30 stuff has the e36 and e31 on them, you'll need another set for the e34 ones.

[e30_kid89]

aahh i see...well @ least the 318iS is covered..thats what i was worried most about..the e34 harness shoudnt be too difficilt - i havent really taken time to look @ it but its SOMEwhat similar to the e36 except for some wire colors & functions here and there.

[Rev Engineer]

Here's my wiring contribution for an s50 -> e30 m3 swap - might also help the m50 and 325i people.

http://www.cityofdust.com/s50/e30%20s50%20wiring.pdf

http://www.cityofdust.com/s50/e30%20s50%20wiring.xls

[FredK]

Taking into account what was posted in this thread and what I found in the ETM, here is an updated pin/function chart for the late model '89 / '93 M50.



p.s. It probably changed my orignal chart posted earlier in this thread because I wrote over the original file when I uploaded the image to my server.

Mike, did this configuration end up working? Can you read codes from the Diagnostic Plug, and can you do a SI reset?

From what I gather, it seems like E36 x20 pin 19 goes to E30 C101 pin 11...

Otherwise, this looks exactly like my wiring adapter configuration, except that I have an early 1989 325i, so I have no red/yellow wire coming out of pin 20.

[Mike B.]

I updated my pin chart and uploaded it to my server. It shows what I used for my running swap and also takes into account the small change to make it run smoother (see thread link) - your 'quote' image is now adjusted to show this. The car ran great until the mishap at the track.

I did not have a code reader, so I couldn't check to see if that function worked. I was unable to do the 'stomp' test.

[EtaSport]

Mike what did you have to change for the smoother running? I'm not having a problem that I know of, but a friend of mine is that may be caused by this.

I can also add, my wiring, which might be the same as above, i'd have to pull my charts, has had no issues, my code reader works, and my Peak tool reset my oil lights. I dont have a check engine light with my cluster, but I was going to add a small bulb somewhere. I was also able to do the pedal test on the blue m50 car.

[Mike B.]

See the thread listed at the bottom of my pin chart. I and possibly others have experienced some backfeeding of 12v through fuse 13 (fuel pump) when connected through the C101 connector. I can't figure out the reasoning behind this and it doesn't make much sense, but it caused issues with the O2 sensor heater. When I bypassed fuse 13 and connected it directly to the E36 harness (Thank Jason89i for the fix) and the engine ran significantly smoother.

I had no 'check engine' light issues with my setup and I know it worked because it was coming on when the alternator was going bad.

Maybe I was just doing the stomp test incorrectly.