had the p0138 code come up, 2 things I noticed looking at the O2 sensor near the cat. 1st, its before the cat I think it should be after, correct?. 2nd, the O2 sensor has 4 spade connectors not a oem harness plug

 

There are 2 O2 sensors, 1 in the exhaust beside the oil pan (well ahead of the cat) and 1 at the rear of the cat toward the rear driveshaft.

 

That code is for the after-cat sensor, I believe. Check the fuse(s) for the 02 heaters in the PDC first. Also check the wiring for frayed or melted insulation or other problems.

 

yeah checked all the fuses, wires are in good shape. but mine is before the cat in the pipe. So i guess someone got cheap and swap the cat for the wrong one

 

being in the wrong place would that throw the code

 

Can the cat be turned around? Maybe the PO put it in backwards.

 

Oxygen sensors are essentially the same for the upstream location and the dowstream location (after cat), except the length of the pigtail coming off the O2S, and the color of the connector; upstream O2S connector has a gray connector and the downstream connector is black. The connector pinouts are the same for both O2S'

The OEM O2S' were made by NTK. NTK O2S' can be obtained from Rock Auto. Upstream O2S is part number 23151 ($34.79), and the downstram O2s is part number 23099 ($36.79). I don't recommend anything but NTK O2S'.

The O2S system ground point is at ground G101 (See pic).



The O2S heater fuse location is shown in this pic (The '97 fuse is F23, but in the same location as the '98/'99).

 

yeah i'll go over everything again, but everything looked good. exhaust needs to replaced so I'll put it in the right spot. thanks

 

I have a 97 jeep Cherokee and It had problems stalling out when I give it gas very abruptly we fixed the stalling problem by changing the idle pressure sensor but now it start to back fire then stall out not like before. What could be the issue? I've already change the spark plugs, cap and rotor

 

I have a 97 jeep Cherokee and It had problems stalling out when I give it gas very abruptly we fixed the stalling problem by changing the idle pressure sensor but now it start to back fire then stall out not like before. What could be the issue? I've already change the spark plugs, cap and rotor

 

The issue is that you are hijacking a thread.