[moved] ecu getting hot thermal paste

Each unit converts its own power and interfaces thru standard 60 Ohm lines or 120 Ohm differential. The DC voltage will be present if the a regulator is working at either end which is trying to transmit, doesn't guarantee it can communicate, but it may be a way to detect if DC is related to the problem or some software glitch or a hardware latch-up issue internally or.... bad part...

A finger test for hot parts is a good method to isolate bad parts, at times.

**broken link removed**

I think problem is occurring due to thermal shutdown of any of Ic in circuit.check out put voltage of voltage regulator ICS when ecu is in work condition and during the time of problem.

Some ICS have internal thermal protection .
Check out whole power supply rails of circuit.you can easily find pinfunctins of ICS by searchñg data sheet .


-regards

Just to suggest a long-shot possibility, since power supplies are mentioned. Did you measure battery voltage at the times the car won't start?

Suppose your voltage regulator is set high. It overcharges the battery while you drive for 30 minutes. You shut off the engine. The battery voltage has not had time to settle. So the ecu detects an overly high system voltage. It refuses to start the engine.

You let the car sit a while. Battery settles, voltage drops to normal. The ecu starts the engine.

Just something I thought should be mentioned. If this were the problem, you would probably have other problems as well.

ok an update for all and whomever might have this issue


I have narrowed it down to ecu. What helped me was the summer in UK as I noticed as soon as the car is started and driving for a bit and switched off, that is the end of it .
no more start or on days that was too hot no start at all even if the engine was dead cold.


What I did was took the ecu and put it in the freezer for 2 minutes and then back in and straight away the car starts

the car starts if you do it straight after switch off but if you wait 1 or 2 minutes then it is dead

so it is 99.9% the ecu and have just bought a new one.


for those that may see this frustrating issue in future, here is a summary :

car does not start
transmission fault comes up(idrive)
fuel pump issue comes up(idrive)
dsc issu comes up ( idrive)
fuel relay pump will continue to run the fuel pump even when the car is off . If you lock the door the fuel pump will shutdown after few minutes

when diagnosed with inpa I can see all those modules are saying they are missing a signal from ecu!

so now my question is what do I need to recode to get the new ecu to work ? is it just the keys and alignment os cas and ecu or more to it ?

Do I have to adjust the VIN ?

When people say close the ecu , what do they mean ?