2001 xj

had a p0155 code so i replaced the bank2 sensor1 o2.
a week later i got a p0104. cleared that.
a week later i got it again. cleared that.
a week later i get a p0155 again!

these are probably two unrelated issues but driving me nuts.

does anyone else have experience with a p0155 coming back after replacing the sensor?
and does anyone know what needs to be done to rid the truck of this code forever?

i hate looking at that damn bright yellow engine light

 

it seems like they can be picky about what brand you use, not sure if they're that picky to throw codes. check part numbers?

 

Here's some NTK part numbers. Do not mix Bosch O2S' with NTK O2S'.


You might try swapping the upstream O2S heater relay with the downstream relay in the PDC and see what happens.

 

thank you for that picture. i replaced the old sensor with the correct ngk new one. 23506. bank2 sensor1.

i read elsewhere that this problem could possibly be caused by a 5 cent fuse either in the PDC or the junction box. i have been getting mixed information about which fuses or relays correspond with the o2 sensors.

 

which fuses in the PDC are those?

 

Here's the 2000/2001 PDC layout. You can see the Oxygen Sensor relays.



Here's the PDC fuse layout. There's only one fuse for both O2S Relays. If it blew all O2S heaters would be inop, but check it anyway.

 

if i already replaced the rear upstream sensor (as p0155 calls for) and the p0155 CEL keeps coming back on..... what is the real problem?

i can't figure this **** out

 

You need to get your truck on a scanner that reads live data. I spent $1200 and two months trying to fix the same problem you're having. Finally put it on a scanner and figured out I had a bad wire in the harness between the O2 and computer. The live data scanner is really the only way to tell what's happening.

 

Problem code points to the circuit not necessarily a component. If one sensor is actually failing they all probably are.

 

What can I do to fix the light forever? I'm new to doing my own repairs.