My 1996 F150 5.0 has a code PO155, where is the best place to start
fixing this?

 

Ok not to get on you because everyone does this but when asking for help with trouble codes please take the time to post the code definition and save us the time of going to Google then back to answer the post. It helps others with the same issue using search as well. P0155 - o2 sensor heated circuit malfunction ( bank 2 sensor 1 ). The heated sensor circuit warms the o2 sensor to move it to closed loop more quickly. So either the wiring to the sensor is bad or the sensor itself. Check the wiring with a multi-meter but odds are its time for a new sensor. I'm not sure off hand such side is bank 1 or 2. I think 2 is drivers side. Personally I would replace both if they are originals.

 

Or the fuse for the heater circuit is bad.

 

Is there a fuse?

 

So is there a fuse,or not? Does anyone know?

 

There must be a fuse and/or fuse link. Look on you fuse panel diagram.
If not there then you will need to find a wiring diagram and look for a fuse link.
Note that '96 was the very 1st year for OBD-II (P codes). Everyone else here has OBD-I which is vastly different. You might want to check out the 97+ forum for some help or at least do a search.

 

Yeah there is a fuse it powers all the O2 sensors It's a 15 amp. On the newer models it's #32. Seems like it was around #24 on the older ones but I'm not 100% sure of that.

 

that code means bad 02 sensor 99% of the time. id start there.

 

It's pretty simple. Just check the wiring for voltage. And like I say if its a 16 year old o2 sensor it probably needs replacing.

 

Other than going to Ford, what other brands of 02 sensors should I be looking at?