2014 Silverado 4WD LT with 5.3L; 148kmiles. ISSUE: Engine light is on and Fan keeps running on high after the engine is turned off. INITIAL DIAGNOSIS: Noticed coolant reservoir was low and my OBDII scanner report shows two codes for coolant thermostat:: 1) 'Pending' P0128 and 2) 'Permanent' P0128. So, I replaced both the Thermostat and the Coolant Temp Sensor and refilled the coolant. I turned the truck on and and Engine light is still there & the the fan roars on high...I let it run for 10-15 min and the dash temp gauge doesn't budge...I shut off motor and fan continues to roar on high for several minuets (which seems to draw down the battery). I Reconnect scanner and same codes show up. Anyone ideas what is going on here or how best to resolve?

 

Update: Turns out I wasn't clearing the code correctly...I didn't have the ignition key switched to "on". Once I switched the key to "on", then clicked "erase codes" on my scanner, the code and engine light were removed and the fan and temp gage are all working fine now.

 

For future reference, even without clearing the code with a scanner, a drive cycle or two after replacing a sensor is usually sufficient for the vehicle to clear the code on its own.