I like to do random code checks on a semi regular basis. Anyone know if this code is something to worry about? Just started coming up. This will come up under stock power or smarty power. I'm on a fresh oil change and oil level is good. I have no leaks and truck runs fine. I am getting no check engine lights. As info I have 83,000 miles on the truck. Just had water pump changed a few weeks ago. I am wondering if this could be a bad sensor. From reading some other posts it seems these trucks tend to have sensor failures on a regular basis. I also tend to have code P0480(cooling circuit) come up every once in a blue moon. Any input is much appreciated. Thanks.

 

Any one? Advice? Input? On the P0521 sensor issue? I'll take theories.

Thanks in advance for anything that might point me in the right direction.

 

I would have the latest ECM flash done first before I started changing sensors.
SYMPTOM/CONDITION:
The following enhancements are included with this software:
1. Improved engine cooling (radiator fan activation) and prevention of possible engine
overheat. When coolant temperature faults are present the radiator fan is enabled
(turned on) during vehicle operation.
2. Correction to oil pressure reading when engine is operating at higher engine
temperatures above 91°C (195°F).
3. Improvement to the Temperature Sensor Rationality Test to prevent possible false test
failures and the following related Diagnostic Trouble Codes (DTC's):
a. DTC P0071 - Inlet Air Temperature Sensor Rationality.
b. DTC P0111 - Intake Air Temperature (IAT) Sensor Rationality.
c. DTC P0514 - Battery Temperature Sensor Rationality.
4. Additional Water-In-Fuel (WIF) warning added to indicate that the operator has had a
WIF DTC P2269 and has continued to operate (drive) the vehicle in excess of 500
miles without draining the water from the fuel filter. The following is the new WIF DTC
that has been added:
a. DTC P0169 - WIF Too Long Error

 

Great information! Thank you, I will get this update done.