I've been trying to get the codes read for my slightly misfiring E30 with the M40 engine. BMW wanted £140 for it, so I sought other options.
I'd heard of the stomp test...now I know that this was ready to work on US cars...it will work with some Euro cars with modification.
I found out that you wouldn't be able to get just any OBD2 code reader and buy a 16pin to 20 pin OBD1 adapter to get the codes.
I found a tool called the B100, which I now know is a copy of a tool made by Peake, they are both handheld scanners made to read the BMW factory codes to give us a good idea of what the car is recording when it finds something out of place/range (fault).
I tried to read the codes with my B100 tool, all I got was E10 code. When I tried to reset the codes (just thought I'd give it a bash) it came up with E11. Both these codes mean that the device can't communicate with the car.
I then found helpful Mr 'TheEnd' on this forum, with some very usefull information from him and some digging around we found that the pin that the ECU would have been connecting to the Check Engine Light (used in the US for reading the stomp test codes), was pin 15.
The information source suggests that you plug the ECU and the ECU connector into a breakout box and use pin 15 to connect to a 12v bulb (simulating the CEL) and the other side to 12v (car battery).
I didn't have such a breakout box, so I stripped a small piece of wire and fitted it to the ECU connector, snaking the wire as smoothly as possible out of the way and basically pushing it back onto the ECU, I then just connected the other end of the bulb to the car battery and had a go. It didn't work as it should: The lamp came on after the first release of the accerator pedal, and after the 5 presses on the pedal, it just stayed on...no sign of flickering...I tried many many combinations of timings but just couldn't get it to give me any codes. I tried turning the engine on and when it was runnung the lamp stayed on and pulsed regularly...about once a second it went slightly dimmer for a split second...this pulse was the same even when the rpm's were increased.
I thought, just for the sake of trying, I'll plug in the B100 tool to check if it was still having issues communicating...it worked! It read that I had no codes ("--") I then disconnected the code reader, started the car and disconnected the AFM with the car running to get it to throw up a code, then I read the codes again and it came up with 07 code! I then cleared the code and it worked!
The B100 tool couldn't reset the Service indicator on my car, but I traced all the connections checking for continuity along all the possible connections and found out that, on my 20pin adapter there was no pin connected to the Service indicator reset pin on the diagnostic port (pin 7), through to the 16pin OBD2 and therefore into the B100. So another usefull bit of digging and help from "TheEnd" I did the paper clip trick...with a wire connected to ground and pin 7 BUT before anyone tries this please read the link!!!! No one takes responsibility for any one trying it and it damaging thier car!...Although it worked on mine!
So all is well!
Thank you to all the really helpfull people on this forum! Especially 'TheEnd' in this case....
Here are the links to the usefull stuff...
http://www.bimmerfest.com/forums/sho...d.php?t=327491 (the Diag port on this link is not exactly the same as mine...there are some pin connectors-female bits, that it states as Not occupied, but they are on mine)
For the stomp test: http://www.bimmerforums.co.uk/forum/...-i-diy-t47837/
Example of a stomp test on a US model:
Attached (I hope) is a Motronic Schematic (still can't work out why this would make it work as the pin 15 has a diode in the circuit...anyone know this?) and the ECU connector diagram.