DIY OBDII to RS232

[gazzy2000]

 chrisjunkie said:

No what pins at the ECU are TX/RX ie pin 3 = TX or pin 3 = RX

I have got an obdii pinout with SSM RX/TX but I need to know it ECU side.

Thanks so much for your help so far Garry it has been invaluable!

hey no worries, i will have a better look 4 ya 2morro.

Thats the joy of using a chocky connector, u can just swap the wires if they are wrong.

Only one way works, and the software wud soon tell ya u hv it wrong coz it dosent work!

[gazzy2000]

(me on lappy no where near my docos)

[chrisjunkie]

Haha yeah good point! I have just found this in the stash of pinouts I have:

Now just to find the one from the TT ecu which is seeming more difficult that I thought!!

[gazzy2000]

yer thats the diagram

if u put the two wires at the obd into the correct ecu plug/pins you cud just cut them at the obd end n put chocky connector there, so u can swap wires easier

[chrisjunkie]

Not a bad point at all. Though I am pedantic and want to do it neatly

PLUS I really cant be assed running all that wire heh...

Where's ReubenH and his mint wiring diagram skills when you need him ;D

[gazzy2000]

righto pedantic boy... ;D ;D

if i recall, its pin 4 & 5 on the OBD plug (the green ones) thats MEANT to be the rx/tx (dunno what way rund) i am not sure but if i recall correctly i tried to trace these wires from the OBD to the ECU plugs and cudnt find them, so F knows where they go.

I also recall some confusion over the location of the ODB pins and numbering, and that screwed me up, so be mindful of the fact that any diagrams you look at of the OBD plug layout, that you are looking at the right pins, either on the fixed OBD plug or removeable plug (male).

The OBD is a standard but some turkeys name the pins different on their diagrams (1-8 etc are not where you think they are because the refere to the removable plug not the fixed plug, if you get what i mean)

SO your idea of running two cables to the ECU blank number 3 & 4 pins on plug 136, is not a silly idea, then you can snip the two greens behind the OBD plug and solder your new ones in.

But if it twere me i wudnt focus on getting it all neat for a start, its quite a mission to get connected so i wud just prove the concept first, then go OTT tidying up sh1t. Initially, i had cables for christmas with the ECU exposed etc, the mess did my head in LOL

Just need to find what way the rx and tx goes, like i say, yud soon know, any software you use will work one way and not the other, so you cud just twist those two wires on for a start at the OBD plug, then onec you have proved the tx/rx are the right way round, solder their asses!

Hope you have a laptop, because phase2 of using this cable is using varoius applications on a lappy to get your ECU ID etc, then hopefully our mate log1call is lurking and can assist from there....we will call that phase3, ;D

[log1call]

Yup, I've been lurking.

Good work Gazzy.

If your sure the ecu doesn't have wires for the diagnostics go to a wrecker and ask if you can cut a plug off the wiring. Then don't often sell the wiring so it should be cheap, well my local is good anyway.

Cut the plug with long enough wire if you can. There are two little plastic flaps that fold over the back of the plug to hold all the wires securely, release the latch on the flaps and flip them open then use a tiny screwdriver to release two wires and pull them out, lightgreen/red and darkgreen/white are what's usually used for the diagnostics. Open the flaps on the car's plug, push the wires in, close the flaps.

As Gazzy says, you won't do any harm if you connect the cable the wrong way so just experiment.

[chrisjunkie]

So I have this kinda working, the ground seems to be really tempremental. Evo scan connects gets one set of data then fails then I wriggle the ground and it comes back etc etc.

I will have a look at my diagrams now as I may just splice into an actual loom ground wire...

[chrisjunkie]

Maybe I will hook it into GND (Control Systems)

Sounds like that may work? Other Ideas?

[gazzy2000]

 chrisjunkie said:

Maybe I will hook it into GND (Control Systems)

Sounds like that may work? Other Ideas?

the earth wire simply needs to be earthed to a good bit of metal, a bolt or a screw, you dont need to run it in the GND system on the ECU or any thing like that.

If you suspect its dodgy you can splice a wire to the black earth wire on that cable and simply screw it down tight under the dash or any other good earthing point for now, just until you have the system working stable.

I know there are certain settings in EVOSCAN that are close to being connected, but it keeps "engaging" then "disengaging", this means the wrong settings are being used, but you are close!

This is where we have to pull out yr ECU ID and the fun begins! There is another smaller program called subaru select monitor that log1call will get you to use to pull yr ECU ID. Hang on i get the link....

[gazzy2000]

when i say ECU id i mean ROM ID.

here is the link http://www.vwrx.com/index.php?pg=selectmonitor

The download is at the bottom of the page, have a read on that page but dont let it confuse you too much at this stage, it all starts making sense in its own sweet time! (this is the site that says tx & rx is pin 12 & 13 on the OBD plug..... wrong! just remember its the green wires on the OBD plug)

EDIT - actually.... log1call, is the Select Mon software the one that lets you pull yr ROM ID? can t remember now, hvnt gt that lappy with me.

EDIT - to answer my own question.. quoted from that page linked above "you can use the SelectMonitorDump utility to identify your ECU ROM ID"

SO there are two features to Selet Mon, one of which is the dump to find the ROM ID, the other is the real time logging, the real time logging is no where near as flash as EVOSCAN

[chrisjunkie]

See thats the thing vwrx (selectmonitordump.exe) is actually set on to the right com port but gives me a ROMID of null... what settings can be changed in evoscan???

[gazzy2000]

 chrisjunkie said:

See thats the thing vwrx (selectmonitordump.exe) is actually set on to the right com port but gives me a ROMID of null... what settings can be changed in evoscan???

Yer, with selet Mon (SM) if you get a ROM ID of null, you arent connected properly i.e. wrong com port being used or tx & rx the wrong way round, or wrong pins entirely

Thats why soldering on to teh ECU you cant go wrong. Get SM working and your ROM ID then worry bout EvoS.

If this means you have to solder on the ECU pins, then so be it, think thats why i ended up doing it, coz any other way was a beatch

[gazzy2000]

Heres a comparison of the Subaru BH diagram (page 27 of 66 from that BH wiring diagram JDM PDF)

and the OBD plug from VWRX site (in blue)

you can see from the BH diagram (second plug down) the two greens on pins 4 & 5.

SO whether its pins 4 & 5 or WHAT EVER, its the greens that are MEANT to be the tx /rx ones.

Have a look on page 27 of the BH diagram, the greens dont go to the ECU on BH chasis.

I suspect ofcourse the v5/6 WRX OBD green wires (or equivelent) will/do

[chrisjunkie]

Ok so I have been trying to get this thing to go, It doesnt connect in evoscan and SelectMonitor.exe gives me weird results...

HOWEVER I can get a rom id of A1100D which returns only a single thread in google...

Maybe my ECU is just not built for this or I am doing something stupidly wrong

[gazzy2000]

 chrisjunkie said:

Ok so I have been trying to get this thing to go, It doesnt connect in evoscan and SelectMonitor.exe gives me weird results...

HOWEVER I can get a rom id of A1100D which returns only a single thread in google...

Maybe my ECU is just not built for this or I am doing something stupidly wrong

OHH yeaa, its a right pain in the ass, not just plug and play *AT ALL*

If you have your ROM ID that is a start, means you hv TX /rx and wiring all sorted, well done!

So that ROM ID is the same as the ECU i was working on and i did get EvoS working on it, but not calebrated properly, that whas what log1cal and i were working on when i stopped helping him.

That ROM ID is one that is not well documented and log1call and others overseas having been working hardout to crack it to get the settings to work with evoscan, i believe they were making good progress and/or may have cracked it by now.

Log1call will be best to answer these questions.

So i am guessing you will be able to get connected as i did, but the data wont make any sense, if you cant get connected i might be able to send you a screen dump of the settings i used.

Its frustrating but hang in there, becasue you will be among the worlds first to get a v5/6 ECU working with evoscan

[chrisjunkie]

Ok cool Garry thanks for that info. From what I have read the ECU's should take the form starting with 7 as 7 means subaru?

I dunno I'm not anything near an electronics noob but this has truely got me stumped!

Any screendumps would be good but maybe I should also try this on another computer/try updating driver

Calling log1call!

[gazzy2000]

hmm heres a screen dump, may or may not help. sometimes when you change settings in ES you have to shut the program and re-open

Yer, putting LOG1CALL symbol in sky, batman styles 8)

[chrisjunkie]

looks exactly the same as mine :-\

What I have discovered now is one polarity of the wires works with SelectMonitor.exe (returns bogus values) and the other polarity works with evoscan (all values are zero)

Dunno if this helps in helping me to get this going! I thought it was going to be simple haha

[log1call]

Hey team, same old problem I see.

The way to connect the wires, is the way that got you the A1100D. I presume that was in the vwrx tools? Connect it and confirm that you can get the id(A1100D), then we can figure why the evoscan got nothing but zeros.

That id number A1100D, along with a few other A***** ids are not well supported. Gazzy and I were trying to find the right addresses(that's the "request", number shown in that screenshot of Gazzy's). I found a few but there are still a few important ones to be discovered.

If your version of evoscan looks exactly the same as that screenshot then I will send you a file with the best addresses we have found so far.

Before that though....

Once you have it connected in vwrx start the evo and check that the program connects. If you make a succesfull connection the "recieved data"/"event log", box at the top right should go green and the ecu id number should be shown. If you get that then you are connected and it's just the addresses that are wrong, or in other words the laptop/program is asking the ecu for data out of the wrong places in the ecu. See how that goes and let us know.

[chrisjunkie]

Ok let me try to explain better.

Out of the ECU I have a red wire and a black wire (not sure which is tx/rx)

I have yellow and orange on the TTL-232r (forget about ground that is connected straight onto the battery)

When red is connected to orange and yellow to black, Evoscan connects and just returns zero's - vwrx doesnt connect

When red is connected to yellow and orange to black, Vwrx connects with bogus numbers but returns the ROM id - evoscan does'nt connect

So maybe I need your evoscan data.xml?

[log1call]

So when the evoscan connects does it show your id number A1100D?

[chrisjunkie]

didnt know you could get an id in the program? How do you do it?

[gazzy2000]

 chrisjunkie said:

didnt know you could get an id in the program? How do you do it?

If i am wrong here Log1call will correct me.....

where it says "select ECU" if your ROM ID not in there, thats where you need to pick one that is close.

- Go through all the ones in the drop down, see if one is close (stop start ES if you have to)

- get a data file that has an ROM ID that is close

- get log1call to give you a data file that contains a taylored file for you.

Pays to really think out side the square when trying stuff, and be thorough too i.e. stop start ES multiple times if need be

[gazzy2000]

you got skype and a web cam + internet whilst working on car?