I have a 2002 3.9l, error codes are 0031, 0037 and 0132. Both O2 sensors have been replaced. I pulled the connector off the sensor and checked the voltage to the heater leads with the key on, no voltage to either sensor to the heater leads. Is this a valid troubleshooting procedure or does the engine have to be running?

There does not seem to be a fuse for the heaters so I am at a loss. The wiring looks to be in perfect condition, but I haven't traced it due to the difficulty of even locating the sensor wires in the harness. Looking for suggestions.

 

In 2001 (and apparently 2003) fuse U in the PDC is for the 02 heaters. Can we assume it is there in 2002 as well?

The ASD relay would need to be energized to power the heaters so no, I don't think your method is valid.

 

Thanks for the tip. Can anyone help me find fuse "U"? Nothing marked as such in the PDC, at least not that I can see.

 

Found! Fuse was completely missing! Hopefully codes will now reset. Fingers crossed!