I have a 2005 BMW 120D in which I cant seem to get a scanner to connect. The fuses are OK. I have tried a bluetooth ELM327, a cable equivalent, and BMW INPA K+D scanners. All fail to connect to a simple OBD such as Torque, and more BMW specific programs. I am thinking that the problem must be in, or beyond my OBD port. I have 12V at pin 16, and earth at pin 4.
Any ideas what to look for next? I have a pinout diagram but dont know how to test for signals.
thejazzpianoma,
Aug 22, 3:02am
Might be time to buy a cheap scope, you can pick one up well under $100 now online I think.
I would test the power and ground again with a test light as it sounds like you have used a multimeter which provides no load of course. From there I would move on to the other ECU powers and grounds.
If that doesn't work, then I would disconnect all sensors etc from the ecu and try connecting again.
Really though, a basic scope is your friend with these sorts of things.
Others may have some more ideas for you. Best of luck.
thejazzpianoma,
Aug 22, 3:04am
BTW, is there a symptom that is causing you to want to connect a scaner? If so that might be a clue if there is a grounded out sensor or some such upsetting the ECU and not allowing you to connect.
intrade,
Aug 22, 3:35am
did we not or did i not tell you before obd2 is emission only. Diesel are only covered under obd2 from 2007 onwards. Some give a few like my 2001 bora obd2 will give coolant temp and mass airflow . Thats it on obd2
intrade,
Aug 22, 3:36am
go on wish and buy a pirated ista- bmw scanner for .
bigfatmat1,
Aug 22, 7:15am
I had a 118 bmw with this problem the other day. on closer inspection a drain had blocked up water level rose below the DME box then entered the DME/relay compartment and filled the DME full of water
bigfatmat1,
Aug 22, 7:18am
You can check the communication lines with a voltmeter but without vehicle details i cant help further
budgel,
Aug 22, 8:23am
What details do you want? As stated in my original post it is a 2005 BMW 120D.
budgel,
Aug 22, 8:26am
Yeah, the airbag/ SRS lights are on. I have fitted an emulator in the passenger seat, and now want to erase the warning lights and codes but cant connect. It wouldnt connect before the emulator was fitted either.
budgel,
Aug 22, 8:27am
Not much point if even a simple OBD tool wont connect.
bigfatmat1,
Aug 22, 5:13pm
What are you trying to connect to? Srs? Have you tried connecting to the dme. Never used cheap tools but obd2 is emissions only. Do any of the tools claim to do airbag codes?
intrade,
Aug 22, 8:29pm
They wont . my idiag launch can do it 4 sure. but i have no software sub its 66$ us for bmw . So eaven if you had comunication your emission tool wont be able to do any resetting. as airbag is not emissions by any of the worlds manufacturer. So you would need a obd2 brakeoutbox and see what communicates on what pin they are labled the lights. i know of 2 toyota with can low shorted. i dont fix it as i am not paid to do so and one of them dont uses the can network at all its just there because next years model might use it. at a guess. I given you all the information already more then once now-OP
budgel,
Aug 22, 8:32pm
I know OBDll is emissions only, my point is I am getting no connection anywhere. I have Deep OBD for BMW, Vehix 411, and Bimmercode, which all say they can reset airbag codes. I also had a specific BMW airbag light resetting tool which I returned because it wouldnt work.
intrade,
Aug 22, 8:39pm
did you do the most simple thing and check all fuses . and emulating a airbag under a seat sounds like you put a resistor there. it dont emulates nothing it just bypasses the seat part of where the plug went. Without a scan you wont know if the problem eaven was there. Anyhow i have to go pull my hoist apart now it made a horrible noise when i lowerd the car yestarday i hope i can get these balls as i heard them crunch and the head was hot to the touch.
budgel,
Aug 22, 8:57pm
As stated in the initial post I checked the fuses. A bitch of a job on these cars! BMW's are susceptible to a fault in the the passenger seat occupancy sensor which causes the warning lights to display. The emulator is more than a resistor. There is a resistor mod which does as you say, but an emulator doesnt bypass the airbag, basically it tells the ecu that there is somebody sitting in the seat all the time. If I wanted to bypass the passenger airbag, these cars have a switch to do that on the side of the dashboard.
bigfatmat1,
Aug 23, 1:33am
check the k line. Pin 8 for voltage. That's the communication wire for airbag. However it's very unlikely there is a fault on the line as you state you cannot connect to dme or TCU. Which use k line pin 7 and two lines are not going to drop out unless a gateway is stuffed but car runs.
bigfatmat1,
Aug 23, 1:35am
I'd be rechecking power and earth at plug pin 16 and 4 under load
Thanks, I'll look at those things, would a test light be better than a multimeter for a load? I can do that tomorrow, loadpro will take a bit longer.
intrade,
Aug 23, 5:18am
the problem with a test light is you could overload it and its only vusual and you need a brakoutbox i you short pins you cause more problems. brakoutboxes on wish are not exactly cheap either. i got my one from hickley at automechanika frankfurt a few years ago.
intrade,
Aug 23, 5:42am
https://www.aecs.net/products/AECS/AECS%20OBD%20Break%20Out%20Box.pdf this is what you would need . My one dont has the voltage readout. with that you could use a test light that dont draws o much and see if you have a voltage drop on the readout or if the voltage drops with the emission scantool connected- If you look each pin has a led ligth to see if its on or not . My one is from hickley but it dont has the voltage readout . The garbage one on tradme has no voltage and no lights i think the wish ones have it all also but they are over 140$ the aecs one is 209$ or something.
thejazzpianoma,
Aug 23, 9:45am
A multimeter on it's own has effectively zero load, so can be misleading. If you haven't bought a loadpro yet, in all honesty I probably wouldn't I have one and almost never use it. Instead I prefer a set of home made test lights with varying known wattages for substituting larger loads. Mostly though I just use a standard incandescent screwdriver style test light, which is what i would recommend here.
You won't overload anything if you are following the wiring diagram as you are testing external powers and grounds that feed the ecu. The OBD power and ground may be monitored but they are designed for external loads like scanners etc so no panic there.
The key thing with test lights is just to always ask yourself, roughly what sort of load am I trying to emulate here?
If it's a radiator fan I am going to break out a couple of my larger headlight bulb style test lights. If it's a small solenoid or something, then I scale down.
Hope that helps.
bigfatmat1,
Aug 23, 6:03pm
also the other thing is are you checking with the ignition cycled twice. ie press start button without foot on brake until all the lights come on the dash not just the first set of lights but the second set. if unsure do it with car running. The modules need to be powered up to communicate. (there are other modules that do communicate with key off but not the srs tcu or dme)
intrade,
Aug 23, 7:10pm
i used the loadpro to find a non wotking tail light in 5 minutes after replacing the bulb did nothing . 30 minutes before i was to be at the wof . mesured voltage drop so went to knowen good ground tested load side no drop on multimeter. So its got to be the ground . followd ground ah there it is was corroded undone bolt sanpaperd it whipped some petroleum jelly on it reasemmbled . phoow tail light works . Drove to wof and passed it. also diagnosed in 5 minutes if my clutch on the ac system had a voltage drop in the harness or not. checked fuelpump wiring harness all the way to the battery with the loadpro all 5 minute test and you know 100% if there is no drop on your multimeter when your pressing that button. Your done. Gona have to do my 95 corolla who i swapped soon you can bet i loadpro the wire harness before i remove the fuelpump from that tank first. Testlight will illuminate . I do have a test light if you just need to know if you have anything at all then a testlight is ok. but it dont tells you if or not the harness is corrosion free.
intrade,
Aug 23, 7:29pm
The biggest problem is when you learn something in ways of habbits . to change is difficult for most people. It was more easy for me because i never learnd it the way they did , i picked what seemd Good from anyone . So if you know nothing the best is to buy dan- sullivans book and loadpro. The book is not a manual to open up what page matches your problem like a flowchart. The book must be read from page 1 onwards and only move on if you understand . if you do not understand use the internet for alternative explenations till it clicks . then move on to next page. This will require effort No one is a born elekchicken. And you have to become a electromechanical diagnostic technition to fix anything that has electronics. that means anything with a ecu. petrol from 80s and diesel from mid 90s Commonrail is far more easy then a abortion of a efi Diesel pump to diagnose. SRS system is standalone i posted TST seminar videos. to get information it takes a hell of a lot of efforts To learn it all but its duable. I already filtered all the crap on the internet out that dont works. Just remember if its to good to be true . then it will be from nothing comes nothing. True fact.
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