hey boss hoss thanks for the reply it is bank 2 sen. 1 i have changed all the senser's also i just put new pipes on from manifold back eliminating 1 cat on each side from 4 total to 2 magnaflow highflow cats and new 40 series flowmasters i do have o2 simulators on the rear o2 senser's is this supposed to keep the check engine light from coming on sorry i guess i should have mentioned it's on a 1998 f-150 with a 5.4 4x4
P0155 indicates a computer-detected fault in the heater circuit for the sensor.
Most likely cause is either an open heater in the sensor, a wiring fault (corrosion, cut wire, bad connector) in the harness to the computer, or the computer itself (it switches the heater on and off when needed).
The service CD contains the procedure to diagnose the fault. Sounds like you need one.
I have a 1996 ford f 250 and I just replaced both o2 sensors and went for my smog and still this came up 1996 sensor code p0155 so I did not pass smog what did I do wrong was I to reset my car some how the check engin light is still on
People, you must read the code discriptions more closely.
155 is the heater ""circuit"" has an open, short or ground.
You don't just jump on the words OX sensor and change them when the fault is not with the sensor.
Use a voltmeter to test if there is 13 volts heater source to heat the sensors.
Do not try to measure the"""OX"""" sensor resistance part of the OX detector but you can test for heater being open.
Likely a short to ground, or an open in the harness or plug to the sensor.
Emissions test will alway fail if any code is set except 'minor' fuel system's tests that are not complete at the time of testing.
When the issue has been found and corrected, you can clear the codes but it take longer for the PCM to do all the retesting of every system by mutiple drive cycles before emmissions will pass.
I traced my problem to a ground wire broken at a plug on the passenger side firewall just below the starter relay. Anybody have any info on this plug. part #? can I replace just one pin in it? ect. ect.