I have a 2011 Tahoe LTZ, and recently my check engine light came on and stayed lit. One of my fans (passenger side) stays on high from the minute I turn on my key to accessory, and stays on even if the AC is off. I have replaced the fan motor relay and it still stays on high. Ideas?

 

if its a ect sensor fault the pcm will command the fan on as a safety precaution. get the codes read and post them here.

 

I've attached the screenshot, P0481 mod $00, cooling fan 2 control circuit malfunction CONFIRMED

 

Turns out it was the ECM.

 

the pcm senses and open in the fan circuit
the 2 fans are controlled by 3 relays. the relays are used to get fan speed variations. start by checking the fan fuses and relays. disconnect the non functioning fan electrical connector and supply it power and grd...if it doesn't spin...replace the fan motor.

ok just saw your post after i already posted this