I put in 2 new O2 sensors before the cats last Friday. I won't go in to what a pain the job was, but after all the blood, sweat, and tears everything seemed fine. Later that day, after several short trips around town, the check engine light came on. A quick scan at Autozone gives me both bank 1 & 2 O2 sensors faults. I have him clear the code thinking maybe they just need a lil time adjust to my truck. Next day after driving for 15 min, light comes back on. I pull the neg battery cable for awhile... no code the rest of the day. This morning it's back, saying the same thing.

The simple answer is to put the 2 old sensors back in and see what happens, but I gotta tell you... I am in no hurry to do that job again. Any chance my engine and these sensors just need a lil more time together to get to know each other better?

'00 5.4l

 

Is it possible that the code was for the 2 rear O2 sensors?

 

It's possible I 'spose. To be honest, I got the readout from Autozone and went straight to ****'n and moan'n. So, that's a question I prolly should have thought of first. Look'n at my print out here... P0135 - O2 sensor heater circuit malfunction (bank 1 sensor 1) P0155 - same (bank 2 sensor 1).

Considering what a pain it was to disconnect the sensor plugs, I may have damaged both harnesses. But, it seems a bit too much of a coincidence to not be the sensors I just replaced. I think tonight I'll be crawling back under there and switching the driver side and see if that bank clears up.

 

You have to push the plugs kinda hard to get them to seat.... You should hear a click it it's engaged all the way... Good luck. The best way to get at the passanger's side plug (2003 model), is to pull the plug off the "hole". It makes it a lot easier to see looking through the wheel well. Yours might be similar. But by far, the easiest and best thing to help ya is to remove the transmission dipstick tube. It is held on by one little bolt. #8 socket will fit it.(I think)

 

After doing some more digging. it looks like the NKT sensors I put in have a different heater current limit than the Bosch. Any one have any idea if this is something I can adjust or have adjusted. I found this in the motorcraft OBD service manual someone had posted in another thread. Seems like if they have both types listed with the amp requirements, I should be able to get my 'puter to recognize the different limits somehow.