i need some help with this. its driving me crazy and i dont have the ability to leave me truck at a shop.

the sensor is good, not sure why but the truck is giving me that code for the post cat (bank 1 sensor2) o2 sensor high voltage. i have no idea why this is going on? anyone else have this problem? howd you fix it? i cant even find a wiring diagram for the post cat sensor to be able to trace it properly. and all the wires are tucked up above the tranny anyway! also, my part time light will illuminate when not in part time, not bright, kinda goes along with how hard im mashing the throttle. i think this can be linked? anyone have any diagrams? or ideas whats up with the code? like what can cause it? is theree a fuse or relay im missing?? im horrible with wiring, so im kinda up against a constant wall when im working on this. besides the cel, the jeep runs perfect. doesnt smell rich or anything. no lag. anyone who can help, please do. id greatly appreciate it.

96 xj
4.0
aw4
with a/c

 

The after cat O2 sensor tattles on the cat if it's not up to specs and throws a code.. My jeep hasn't done it, but my Lincoln did. I messed up the cat driving it too long with a faulty coil causing a too rich condition. I'm not gonna spend $500+ on a new cat, so I bought an adapter made for spark plugs. They fit perfectly for the O2 sensor too Thousands of miles now and no more 'bad cat' P-code. I found some online at awfulzone
http://www.autozone.com/autozone/par...uler/_/N-9n8cq

The O2 sensor will throw the code if the cat gets below something like 96%, so you won't be killing the ozone layer Hope it works for ya.

 

How are you sure that the sensor is good?

Here is a link with more on your code. Wiring definitely is in play.

http://www.obd-codes.com/p0138

And for that dim part time light, anytime I see anything of this sort, I freshen all engine grounds. Even if it isn't root cause, you gotta start here and eliminate it as a possibility.

Good luck!
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Grounds can be the root cause of many electrical gremlins. Refreshing grounds is NEVER a bad idea, and the investment of your time in this procedure is always well worth it!

You can't tell much of anything by looking at ground connections!! You must remove, scrape, clean until shiny the cable/wire ends and whatever they bolt to. Be sure to remove all paint from any ground connections.

Start with the one on the back corner of the head, and where it attaches to the firewall, as it deteriorates over time and is an area that makes it susceptible to damage. Best to replace that woven cable with a #4 or #2 gauge cable. You can attach the one end to the intake manifold if you would like.

Next go over to the engine dipstick tube stud. Remove the nut and clean the wire ends and scrape the block until shiny at the stud. Reattach tightly.

If you are so inclined, add at least a #6 cable from the negative terminal of your battery to one of the bolts on your radiator support.

 

Which one did you use? And how does it work? Will adding this help me pass smog??