P0138 and Oxygen Sensor wires

(1998 xj 4.0L Aw4)

Hi guys,

A while back i had my rear driveshaft rip my downstream Oxygen sensor wiring harness apart. I purchased a new O2 sensor and now im having some trouble splicing the harnesss to the new Oxygen sensor back together. The new sensor has two white wires, a grey wire and a black wire.

Does anyone know the function of each wire and its correspondence to my Xj's wiring harness?

I took a look at the front O2 sensor and spliced them the same but im still getting a pending P0138 code on my handheld code scanner.

Would splicing the two white wires on the O2 sensor wrong cause it to throw a check engine light.

The harness wire colors:
Brown with yellow stripe
Green with white stripe
Solid black
Light brown with white stripe

Any help is greatly appreciated! Thanks.

If you look at the O2S body harness connector you can see 4 pin sockets. Put the connector lock at 9 o'clock. The following is the hook ups. (O2S side will be the mirror configuration)

Pin 1 - 11 o'clk pos. O2S White - harness DB/WT - Fused ASD Relay Ouput

Pin 2 - 1 o'clk pos. O2S Gray - harness BK - Ground

Pin 4 - 5 o'clk pos. O2S Black - harness TN/WT - O2S Sensor Signal

Pin 3 - 7 o'clk pos. O2S White - harness BR/YL - Sensor Return

Edit: Pin 1 is power to the O2S heater from the ASD Relay circuit - Pin 2 is the ground path for the O2S heater.

You may want to check the O2S heater fuse in the PDC when you finish your hook-ups. The image below shows the O2S heater fuse location.

Here's an edited pinout: (finally got it right)

If you look at the O2S body harness connector you can see 4 pin sockets. Put the connector lock at 9 o'clock. The following is the hook ups. (O2S side will be the mirror configuration)

Pin 1 - 11 o'clk pos. O2S White - harness DB/WT - Fused ASD Relay Ouput

Pin 2 - 1 o'clk pos. O2S Black - harness BK - Ground

Pin 4 - 5 o'clk pos. O2S Gray - harness TN/WT - O2S Sensor Signal

Pin 3 - 7 o'clk pos. O2S White - harness BR/YL - Sensor Return

Edit: Pin 1 is power to the O2S heater from the ASD Relay circuit - Pin 2 is the ground path for the O2S heater.

Thanks sidewinder CC for the great info, I'm going to check it out today.

Wiser said:

(1998 xj 4.0L Aw4)

Hi guys,

A while back i had my rear driveshaft rip my downstream Oxygen sensor wiring harness apart. I purchased a new O2 sensor and now im having some trouble splicing the harnesss to the new Oxygen sensor back together. The new sensor has two white wires, a grey wire and a black wire.

Does anyone know the function of each wire and its correspondence to my Xj's wiring harness?

I took a look at the front O2 sensor and spliced them the same but im still getting a pending P0138 code on my handheld code scanner.

Would splicing the two white wires on the O2 sensor wrong cause it to throw a check engine light.

Yes, P0138 is O2S input (to PCM) voltage too high. If you put Pin 1 - 11 o'clk pos. O2S White - harness DB/WT - Fused ASD Relay Ouput to Pin 3 - 7 o'clk pos. O2S White - harness BR/YL - Sensor Return, the sensor return voltage would be 12 volts (too high).

The harness wire colors:
Brown with yellow stripe
Green with white stripe
Solid black
Light brown with white stripe

Any help is greatly appreciated! Thanks.

Click to expand...

See edited connector pin outs above.