Has anyone experienced this before?

(Bank 2 Sensor 1 O2 heater circut)

Changed the O2 with a new Boshe from Auto Zone, cleared the code, came back, cleared it againg, completed a drive cycle came back..

1998 f150 5.4

 

not sure if its that exact same code but about a week ago my engine light came on and the mechanic diagnosed that it was the o2 sensor. he told me that the sensor might have just screwed up. erased the code and haven't had the light come back on. didn't replace anything. just told me to come back if my light came back on. may be just a fluke like mine.

 

You may not be getting voltage to the heating element of the 02 sensor. You will need to check it at the plug that plugs into the sensor.
It could be as simple as a blown fuse for the 02 sensor heater,if it has one. Could be a broken wire.

Here is a video that gives you a basic rundown. Not an F150,but same concept.
http://www.youtube.com/user/Wellstec...30/RKpbsJZatWo

Or

 

I had the same problem, Turned out to be an elbow on a vaccum line under the front of the throttle body, Kinda looks like a spark plug boot, Mine had a hole warn in it, Very easy to fix, The elbow is about $20 at a dealership, I also had other vaccum lines wear down since, I just replaced them with heavier hose of the same diameter form a local car parts store, No problems since.

 

A code P0155 may mean that one or more of the following has happened:

• O2 Heater element resistance is high
• Internal short or open in the heater element
• O2 heater circuit wiring high resistance
• open or short to ground in the wiring harness

Possible Solutions

• Repair short or open or high resistance in wiring harness or harness connectors
• Replace oxygen sensor (cannot repair open or short that occurs internally to sensor)

Does that help some? I hope so. Good luck

 

Second the vacuum end assembly elbow going into the intake. Same problem its a bad part an common problem