I have a 2004 5.4 4x4 lariat f150 55,000 miles newer body style. The truck has knn fipk kit, ud pulleys, dynatech LT headers, magnaflow exhaust and a custom tuned gryphon. I have been running the tune and headers for a good 4 to 5 thousand miles with no problems. Today my check engine light came on and my gryphon gave me two codes p0054 heater resistance bank1 sensor 2 and p0138 oxy sensor circ hi volt bank 1 sensor 2. If anyone has any ideas please let me know. thanks

 

clear the codes and see if they come back.
i've never seen the resistance code but the high voltage code was usually the sensor. probably need both sensors. but clear the codes first
or if you can turn off the rear o2's with the gryphon then i'd do that because the front are the ones that mess with the a/f ratio and such.

 

thanks for the response, i will turn it off and see what it does.

 

the light came back with a lean code so i replaced both rear sensors and reset the computer light has been off for 500 miles and counting thanks for the help