[CATAHA]

I mean the temperature indicator has up to overheat when the engine run a few minutes, but it goes to zero when engine is cold

I will check on Monday the coolant temperature in a lower radiator hose.....
will keep you update on monday night

Thanks

Also have you checked for Engine compression or Air in system
Because when Temp-Sensor at radiator hose show different temperature then sensor at cylinder-head dme will not start the fan(i had that on many M52TU-525i/528i/530i/328i/325i/330i engines)
Today i did timing for m62tu(x5) and as i was testing for marks, i did not connect many sensors..... so the temp at Speedometer went to red as soon as i put key in 2-nd position, then i plugged in and in matter of 45-sec ~ 1 minute gauge came back to cold

Also This (H.E.R.E) kinda explains a little
and on A/C site... if it shows over pressure fan WILL NOT start

Kinda old car but idea is the same



and the security part, you need to flash and re-vin DME with tool32(BMW Standard Tool Suite) and then Sync EWS with DME

[doktorabg]

ECU for fan is common problem on BMW.

[hcip]

He said he already changed the fan, but the new one could be faulty as well...

The basic method of testing is:
Check wiring and fan...
Basic multimeter tests first on supplies/grounds


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I am sure the Fan that installed by BMW personnel is good, because I test it with a Squarewave pulse and the fan is working
the car was arrived late in night yesterday so I am not able to check the sensors
I will check it tommorrow and some advise from the members of this forum.

Thanks for all suggestions..

I will report tomorrow night the result

[hcip]

DME is really faulty, no pulse from DME to Fan Control module

PROBLEM SOLVED

Thanks to all of you