I have an 01 jeep grand Cherokee lerado 4.0 engine I just replaced the engine with an 04 grand Cherokee lerado 4.o but the 04 02 sensors dont fit. So I put the 01 sensors in it new and the check engine light comes on so I unplug the battery then I drove it for 100 miles and the light came back on. Im stuck please help.

 

Did you even attempt to get the codes read?

 

Yes I had the codes read they were p0031, p0132, p0135, p0141, p0161

 

You need to be more descriptive in your posts, then. Include that information if you want us to help you.
p0031=o2 b1s1 low voltage
p0132=o2 b1s1 high voltage
p0135=02 b1s1 circuit malfunction
p0141=02 b1s2 circuit malfunction
po161=02 b2s2 circuit malfunction
First thing to look at is your harness. Broken/shorted? Check the entire length of the wires, and use a meter to verify. I would also get the proper sensors for it, maybe something changed between years. Old sensors may also have been bad, or on their last legs.

 

I put new ones in and got these codes and the 04 sensers dont connect to my 01 connectors.

 

Well, they must have changed something between years then, probably not compatible, voltages may be completely different, wiring might be different, who knows? Maybe you need to find a schematic, for both years, and see if you can splice the harness in. Best I got for you.

 

Based on your codes I'd start looking for melted and chewed up wiring. High voltage codes mean that the heater circuit (+12V from the battery) has been shorted to the PVM input (~1V sensor feed)

As for the sensors not fitting, did you buy the OE sensors? All four are NTK 23139 (B1S1), 23140 (B1S2), 23138 (B2S1), and 23141 (B2S2). Universal-type requires modification of the harness.