code p0031 in a 2003 cherokee 4.0..Lost!!

[v8only]

Hello, got code p0031 in the 03 2wd cherokee and have replaced #1 o2 sensore before the cat with two different dealer o2 sensors.

the ecu has also been replaced.

completely lost here. p0031 will NOT go away, and we can't get this thing through california smog.

any ideas here?? Thanks all..Jeremy

 

[SteelHeadz]

Cherokee or Grand Cherokee?. K1 Body (CKD) Cherokee or X2(China) Cherokee. I'm confused. Here are the possible causes for the P0031.

O2 HEATER TEST
O2 SENSOR HEATER ELEMENT
(F142) FUSED ASD RELAY OUTPUT CIRCUIT OPEN
HEATER CONTROL CIRCUIT OPEN
HEATER CONTROL CIRCUIT SHORTED TO GROUND
PCM​

TEFrom the looks of it , youv'e STBy the s
FF

F

 

[SteelHeadz]

From what the possible causes VS what you've already replaced, it looks like an electrical issue. Check the Fuses on the PDC first.

 

[v8only]

pdc? I assume you're talking about the primary fuses?

It's a grand cherokee.

I'll check all the fuses....Thanks!