hey guys, i have an '97 ford ranger with 3.0 and the check engine light came on. The codes are 135,141, and 155.
135 = upstream o2 sensor heater malfunction(bank 1)
141 = downstream o2 sensor heater malfunction (bank 1)
155 = upstream o2 sensor heater malfunction (bank 2)

I just replaced all 3 O2 sensors (2 upstreams and 1 down stream) what else could it be?
i would appreciate your help.
hey cctxfish, maybe once again you can help me.

 

the chance of the three going bad is almost impossible if all are heater malfunction the first to check is the fuse for these circuits 10 amp i believe if its ok you probably a wiring problem shorted or broken wire

 

thanx hocheyhitman69, there was a blown 15 amp fuse in the fuse box under the hood and that seems to cure the problem.

 

Good job! I never had a chance [sm=exactly.gif]