Pesky P0137

[Lost_Wrench]

Last winter my 98 XJ was giving code P0171 so I replaced the downstream O2 sensor and in doing so I discovered that the wires to the sensor had been mangled by the driveshaft, and somehow the wire plug/harness itself was also badly damaged so I had to cut it off and splice the wires directly without the harnesses. I took careful note of which wire was which to splice the correct wires together, and used crimp connectors. It took care of the P0171 code, but exchanged it for P0137 indicating incorrect voltage or a short to ground coming from that sensor. I have rewired it twice now thinking one of my connections is bad, and I can sometimes go several hundred miles and several hundred start up cycles before it comes back, but it always does, usually after a day or two of driving. I have no driveability issues and my gas mileage is still the typical 15-19 mpg.

I suppose my next step is to find a new or used harness and splice it back in with a new 02 sensor? Or could I be missing something somewhere else?

 

[Vince]

I had a similar fault when my harness and plug and socket got melted on the exhaust. I couldn't find a new harness or a new replacement connector for the harness. I bought a used pigtail with the correct connector from eBay and rewired all the way back to a branch from the main harness.


For my first fix attempt I used crimped joiners and heat shrink tubing, but I got a check engine light the next day. I redid the repair soldering all of the joints and it has been working fine.

 

[Tim_MN]

Only use NTK O2 sensors, never Bosch or generic store brands.

Use solder and waterproof shrink tube.

 

[Lost_Wrench]

Thanks Vince. I'll have to look for a used pigtail and basically do what you did I think.

I did put a Bosch in, I'll go with NTK when I swap it out, thanks.