Ok here goes. First post.

I'm having a problem with two codes on my 2005 lr3. P0036 and p0056. The Amber check engine light illuminated not long ago but the truck ran perectly fine with no notable issues. When trying to get my inspection sticker these codes made me fail. First thing I did was changed both downstream o2 sensors. Still throwing the codes with new sensors installed.
I am thinking that there is an issue with power or ground that relates to the heater element in the sensor. I've checked the resistance for the heater circuits on both sensors and they seem to be fine. (Meaning I've replace two sensors for no reason). A seemingly simple fix has turned out to be a very big headache.

I don't know where to go from here but to bring it to the dealership and pay out big money!!!

Any help is appreciated.

 

Did you clear the codes when you installed the new sensors?

 

I did not. Everywhere I've looked and even the guys at the local dealership and people st Atlantic British said once I go through the drive cycles it will reset on its own after a few days. It has been over a month now.

I did try to reset it by unplugging battery for a while then reconnecting. The cel goes away for the entire first time the truck is ran. But as soon as I turn it off and restart it the cel light and the codes reappear.

 

Were you able to resolve this? I have the same issue with my 05 LR3 4.4L.. had my local shop test the old sensors that I replaced and they were still good, but even after replacing the old ones with new sensors, CEL still comes up with P0036 and P0056. Same behavior as yours.. I can clear/reset the codes and they go away, take it out for a drive and come back to the house and still no CEL, but as soon as I turn the engine off and then back on again, the codes come back. Any help is appreciated.




P0036

 

Were you able to resolve this? I have the same issue with my 05 LR3 4.4L.. had my local shop test the old sensors that I replaced and they were still good, but even after replacing the old ones with new sensors, CEL still comes up with P0036 and P0056. Same behavior as yours.. I can clear/reset the codes and they go away, take it out for a drive and come back to the house and still no CEL, but as soon as I turn the engine off and then back on again, the codes come back. Any help is appreciated.




P0036

 

I have not dived into the shop manuals for this one, but tossing this out there. Have you checked to see if there is a relay for the O2 heated circuit or a fuse? Usually heated circuits are fused, some also use a relay. I would check those first. Check into that if you can.