I can't seem to get rid of P0130 , P0132 and P0443 . I have replaced 4 O2 sensors and thier corresponding relays as well as the emision canister valve . What am I missing ? Any ideas ?

 

What year is your Jeep?

 

The other thing that you might want to do is to check your wires before the connector. The factory wires. Sometimes the wires get burned, pinched, or the insulation gets removed causing a short. This is for the P0130 and P0132 codes. I am not too sure about the other code yet.

 

Oh yeah, what engine is in it? You said you replaced 4 O2 sensors?

 

I've have checked the harness for any damage . None was eveident , however I did check all the connections I could . Oddly enough everything is good and tight . After more investigation with a OBD2 meter that supplies more detail , these are the issues it has reported:
Codes: P0130 -O2 Sensor Circut Malfunction ( Bank 1 , Sensor 1 )
P0136 -O2 Sensor Circut Malfunction ( Banlk 1 , Sensor 2)
P0442 -Evaporative Emission Control Purge Valve Circut
These were listed as Incomplete
Catalyst Monitor
O2 Sensor monitor
O2 Sensor heater
EVAP Systems monitor .
I've also swaped out the throttle position sensor figuring if it was sending bad information then this could trickle down to O2 sensor readings not being within the parameters and therefor showing a fault . For the icing on the cake , the Jeep won't start at all . Even a shot of starting fluid makes it just stumble . Fuel pressure is about 48-50 lbs at the fuel rail port . I'm now leaning toward an ECM issue .
The Jeep is the XJ that was manufactured in the last half of the model year . It has ( I believe) the california emissions system on it . I think I'm looking at 3 separate cats . One for the front 3 cyl , one for the rear 3 cyl and one directly before the muffler . The O2 sensors are located befor and after the two cats directly next to the motor , there are no O2 sensors befor or after the cat directly ahead of the motor . Have I completely confused everyone yet ?

 

OK!, circuit malfunction means you are looking for a wiring problem or internal issue with the pcm, if your handy with a multi meter I'll post up some diagrams to help you pinpoint the cause of the circuit faults.

 

By the way P0442: means evaporative emission small leak detected 0.020", has nothing to do with the purge valve, although your year Cherokee has what is called a "leak detection pump" which often fails. Don't change it for the hell of it though, always test the part first.

 

Fuse 10 for the F20 circuit ,check to see if this fuse is popped, missing or not receiving power.
If you now have a no start condition, 1. Check the White wire that goes to the Transmission Range Switch (TRS). Check the wiring for short to ground.

2. Check the Brown/Light Green wire from the TRS to the back-up lights for short to ground