Cam positioning sensor gone maybe?

[UrS4boy]

...So if that is actually literally short to ground without any resistance, eventually the ECU will shut down it's 5V reference (and everything else) to prevent damage, thus the engine will die, and without a hall sensor signal it will not start up again.
Source: M2.3.2 factory electronic schematic from Bosch

Can you share that diagram with us? I only have the general schematic I modified for my AAN ECU pin-out post:

http://forums.quattroworld.com/s4s6/msgs/21009.phtml

[quattro84]

So this means that if i short one of all these sensors (fed by the same Vcc) get scaled down by the AD converter? I hope Vref for the ADC is not equal to Vcc?
Sounds tricky... Can't/isn't the board secured with some pull-up/down cicruitry to limit max current for the hall sensor? No need for big power here, since it is more alike a blinking LED for the ECU.

I am too lazy to have a look at the manual, don't think i can find it though.

[UrS4boy]

Just heard my name being mentioned all the way over here
My S2 has been fine since I changed G40 over a year ago, 65535 has not showed up since and my ECU didnt go pop. It was the short to ground causing issue. This could have been a wiring issue, but in my case it was G40 itself that was shorting to ground. Regards, An "irish" guy.

Thanks for chiming in with the latest update. Especially that you noted that the original 65535 fault was not permenent or fatal as prj implied it was and that it went away after you changed the G40 Hall sender. To me, your investigative work helped to confirm that something that I knew had happened, against all logic, i.e. a G40 fault stopped a running AAN (or ABY or ADU), was indeed something that was real, not an unsubstantiated anecdote. Without your post and follow-up (the oscilloscope "sketch"), it would not have be confirmed as well as it has been. Thanks.

[prj]

So a malfunctioning G40 *will* cause a running engine to stop running

It *might* cause the engine to stop running, just like a short in the power supply can.
Depends on the failure.

But if you unplug the sensor, the engine can run indefinitely.

[prj]

Can you share that diagram with us?

No, sorry.

So this means that if i short one of all these sensors (fed by the same Vcc) get scaled down by the AD converter? I hope Vref for the ADC is not equal to Vcc?
Sounds tricky... Can't/isn't the board secured with some pull-up/down cicruitry to limit max current for the hall sensor? No need for big power here, since it is more alike a blinking LED for the ECU.

I am too lazy to have a look at the manual, don't think i can find it though.

There is a resistor and a small filter cap on the input/outputs, but for some reason I have still seen the ECU go nuts when that output is short to ground or rather when funky interference is placed on it. It is very rare, but nonetheless I have seen this happen (also the 65535 error).
Basically, it won't die/burn, but some things sometimes stop working correctly.

[Nik0las]

Small update! I checked and Link/ViPec - ECUs read constantly from G40!

[prj]

Small update! I checked and Link/ViPec - ECUs read constantly from G40!

Did they tell you why?
Motronic also constantly reads G40, but it does this to check the signal. For example to detect if the belt has slipped one tooth and then disable boost control and so on, to prevent further damage.
But it does not really use it for any engine management related things, that is why you can unplug it while it's running and there is no stutter or miss at all, and the engine keeps running.