E36 M50 : suddenly can't diagnose

[masCh]

Hi all

I have an E36 which I used to run INPA and Carsoft on.

I havent diagnosed it in over 6 months, and this is the first time I'm having this problem.

If I plug in an INPA cable, the battery is on but the ignition isn't. The cable has been modified to connect to the ignition pin on the 20 pin connector. But INPA doesn't pick the ignition up. It also cannot communicate with any modules.

Carsoft 6.5, which has worked reliably for more than 8 years, also gives me an error "Module Does Not Respond" when trying to diagnose the DME.

Now to isolate whether the problem is with the car or laptop or cable, I used the same laptop and the same INPA cable on my E46 with the 20 pin connector and everything reads fine, the ignition signal is picked up too. So it is not a software/driver issue, I think maybe the car doesn't output (or corrupted) the data on K/L lines. What should I check? (also tomorrow I'll run a voltmeter to the ignition pin in the 20 pin connector to check if it good)

Cheers all.

[conway]

Perfom the stomp test

[masCh]

What's a stomp test?

Btw I think I may be on to something. I tried to reset the service interval meter manually today by shorting pins 7 and 19 for 4 seconds and it didn't work. Pin 19 is supposed to be ground, so I shorted pin 7 to a screw and it worked. I think I have a problem with the ground. I don't know what I'll do yet but i'm open to ideas.

[David Mc]

Check the battery voltage and fuses on your E36. Battery voltage should be at least 12.6v measured at pin 14 (battery +) and pin 16 (ignition +) of the 20 pin diagnostic port under the hood. E36's are also prone to the ignition barrel collapsing, which can result in poor or no switching of the ignition signal. This problem is almost certainly related to low vehicle voltage.

[masCh]

Voltages are fine. Cables are fine.

Got it working today. Apparently if I switch off the engine (but retain position 2 on the ignition) it is ok, I can read the DME and ZKE. (But I can't read other modules Airbag, EGS, etc still). As soon as a turn the engine on, INPA throws an error and nothing responds anymore.

So although DME can be read here, I will never get live data unless I figure out what's wrong with this ADS interface.