[SOLVED]820-3476 fan on high immediately. Boots normally.

[bjf]

I have a liquid-damaged 820-3476 that appears to be working fine except the fan spins up high as soon as it receives power. It doesn't matter what is plugged into it. It boots normally, doesn't really seem obviously slow. I ran the online Apple test and it came back with just a fan error. New fan doesn't change anything. I pulled off the diagnostic connector but other than that I haven't done any repairs. Just ultrasonic. I attached pictures if anyone has any ideas of what could be causing this. Not sure where to go next with it.

 

[Repairable]

where was the spill?

also apple online test sucks mayor, its something like a car mechanic that tells you "your engine is broken"

run asd to see what sensor is damaged, high fan is most likly sensor issues

 

[bjf]

thanks, been working on a lot of 2015 boards lately and forgot that 2014 has an ASD. check the pictures for location of the spill.

 

[bjf]

Ok, ASD gives me Sensor Group #5 failure. IC2C, IC0R Sensor reading below low point.

 

[dukefawks]

IC0R will not cause fan issue. Run EFI version of ASD and let it continue on errors so you see all of them.
IC0R is U5400, probably corroded pins on that one for a start.

 

[bjf]

Ok, will do. Checked U5400. Nothing at all around U5400. Area looks good and voltages seems good. Same as good board.

 

[bjf]

Ran EFI. Only reported fan error. Sensors all came back fine.

 

[bjf]

Regular ASD is also now giving only fan errors.

 

[dukefawks]

Bad fan or connector. Or in rare cases the SMC.

 

[bjf]

ASD didn't lie. It was Q6060 so the fan had no rpm control signal. Done. Thanks.