I just want to make sure I understand this right,
Pin 38 goes low once some preliminary checks within ECU and stays low until unrecoverable error or switch off.
Or better yet the MFI relay is switched on whole time when key is in IG/ACC.

Am I right?

 

I do not know the answer but may be you could read from the attached circuit. Pin 38 is connected from battery through this MFI relay - into ECU. I do not know what this MFI relay does.

 

It basically switches the power to engine electrical components, and I have seen this in manual also, but the question is if it flip-flops anytime when in operation.

Vdaka, vidim ze manualy citame iba my na Slovensku.

 

That relay powers components critical for operation (e.g. fuel injectors), so I don't think you're going to ever see it turn off while the engine is running normally. My experience (matching the manual) is that the ECU turns it on when the engine is running, and leaves it on for a short time after the engine is turned off (I've heard 5 seconds, but I've seen it stay on for 10).

 

Ok, thanx a lot, it seems I have correct understanding of it.

 

But I see the same behaviour (staying on for cca 5 more sec) also on the pin 12 and 25. So I do not know what is the difference between 12,25 and 38 in terms of uninterrupted power supply.

 

the difference is that pin 38 goes low and the coil of MFI relay switches the power supply to 12,25 and many other places, so actually uninterrupted ECU power supply is at pin 80 (not considering blown fuse)