Need help with computer codes big time.

Went to Autozone for my problem I keep having with my 97 XJ 4.0. I already have replaced both O2 sensors and reset the computer but today the check engine light came back on so I took it to get it checked out.

The computer spit out two codes, 135 and 141.

135 Reads:

The pcm has determined that a malfunction exists in the heater circuit for oxygen sensor 1 in bank 1 (pre-cat).

141 Reads exactly the same thing, except for the post cat O2 sensor.

What gives? Am I missing something? They are brand new and I unhooked the battery for 30 mins or more.

Need some help big time.

Thanks,

Double Down

Check that the heaters are heaters are getting 12 volts to them. You'll need a wiring diagram to figure out which wires those are.

Check and make sure you have the right O2 sensors. As PaulJ stated. You need the type that have heaters in them. The heated ones have a metal cylinder where the wires attach, that is about twice the size of the part that goes in the manifold and cat outlet pipe. Just my .02.

Andy

Pretty sure I have the right ones, they are the Bosch Jeep XJ 97 pre-cat and post cat O2 sensors found here http://www.autopartsauthority.com/oxygen/jeep~1997~cherokee~sport~parts.html

And they were the plug in kind, not the 3 wire deal.

Also, how can I get a wiring diagram because I am going to try to figure out what is going wrong this week and try to check the power to them.

Chris

Factory Service Manual will show you the wiring diagram, and it's a good investment. Between the FSM and a Haynes you can figure out just about anything.

Kevin