Hey guys, I purchased a 2000 Jeep Cherokee about a month ago and I've got a CEL on. The following codes are coming up, p0456,0432,0420.

I replaced the muffler and the catalytic converter, I also replaced the EVAP canister. I reset the light, and it came back on. I was wondering if anyone else has a similar jeep model and expierienced some of the same symptoms and would be willing to tell me what they did to resolve the problem. I dont want to throw anymore parts at it unless im completely sure. I'm thinking it might be the O2 Sensors..but I'm not sure.

This is a 2000 Jeep Cherokee Sport 4.0L I6. California state emissions (atleast thats what the sticker says).

Also, I cant seem to find the O2 sensors, there arent any on the catalytic converter, there doesnt seem to be any ports for it either. Any help is appreciated.

 

The should be s sensor on the exhaust manifold or just below it on the downpipe and the other should be in the second cat, the wires come off the back of the tcase harness. See if you have a plug dangling around up there.

 

Just checked the Chrysler service manual. All 4 of my O2 sensors are on the mini catalytic converters in the engine bay. I do not have any O2 sensors on the inline cat. Now the issue becomes whether I need a new exhaust manifold with 2 mini cats, or I need 4 O2 sensors. The codes code for low Bank 1, and Low Bank 2. does that mean the 2 bottom O2 sensors? Or the 2 top?

 

On a 2000 California/50-state XJ you have THREE catalytic converters and FOUR O2 sensors. There's the big one in front of the muffler but it's more like aftertreatment. The others are in the exhaust manifold. There's a small cat for cylinders 1-3 and a small cat for cylinders 4-6. These are bank 1 and bank 2, respectively. Each cat had its own O2 sensors, upstream are Bank 1 Sensor 1 and Bank 2 Sensor 1, downstream are Bank 1 Sensor 2 and Bank 2 Sensor 2.

P0456: Small evap leak. This is tripped by evap system pressure close to atmospheric. Check vacuum lines near the gas tank and the gas cap. There are some plastic lines (tasty to rodents) and steel (rustastic) that can cause leaks. Of course the gas cap may not seal right.

P0432: Bank 2 cat efficiency below threshold. This code is determined by B2S2 oxygen sensor's signal looking too similar to B2S1's. The oxygen sensors are really only good for 80k miles anyway so replace them before tearing into the manifold. You can find OEM NTK units on Rock Auto for pretty cheap, as they're a wear item and effect fuel efficiency I recommend replacing all four. I also suggest doing a tuneup and looking at the old spark plugs. Spark plug deposits are an excellent indicator of any problems like running rich.

P0420: Bob Marley - erm general cat efficiency below threshold. This will come on with P0432.

The big cat is not monitored.

 

It should say what sensor bank 1 includes cylinder 1, bank 2 is the other. It should say, for example bank 1 sensor 1, which would be the first sensor on the bank 1 exhaust

 

do you have the evap canister at front under hood and or under vehicle at rear?

 

It is right by the gas tank. Underneath the car.