[westslope]

Looking for advice and suggestions, please.

A few days, the SES light came on. I checked with OBD-II android scanner Torque Pro, and received the following 3 codes:
Current fault: P0157 B2S2 low voltage B2S2 = Bank 2 (driver side) and Sensor 2 (downstream)
Pending fault: P0158 ... high voltage
Pending fault: P0157 ... slow response.

Torque Pro also showed the O2 sensor B2S2 volt readings as initially wildly fluctuating, then the volt readings settled down to 0.28 to 0.31 volts range. All these symptoms point to an O2 sensor or wiring/ground failure.

I crawled under the vehicle and could see that the O2 sensor harness and plugs were unattached and floating freely. They were rubbing on the drive shaft. The insulating cover (for all 4 wires) had been split. Individual wire insulation was removed for two wires on one side. The actual copper wire was diminished or broken in two of the wires. It is probably not copper as per early 2010's post below.

In the photo below, the red arrow points to the metal tab with hole where I believe the harness is plugged into.

Should I attempt to repair the existing wires by soldering in new wire? And if so, what gauge of wire would you recommend?

Or should I just order a new B2S2 O2 sensor?

The vehicle currently has new Nissan 02 sensors in the back, installed in autumn 2021 when I had the primary cats replaced: Nissan Heated Oxygen Sensor 226A0EA200 (driver side) and Nissan Heated Oxygen Sensor 226A0EA210 (passenger side). That turned out to be quite expensive as partsouq.com charged for shipping and FEDEX charged for customs duties and taxes.

With no additional charges, I can easily order from partsavatar.ca a Bosch 16513 for C$119.35, NGK Canada 24244 C$92.79; DENSO 234-4297 C$108.23. The dealership in Kamloops wants C$300 for the Nissan sensor. Amazon.ca and Napa Auto are far more expensive than partsavatar.ca for Bosch, NGK and DENSO sensors.

Xterra owners seem to have good luck with Bosch, NGK and DENSO sensors. Does it matter which one I order?

I have now used all 3 brands for A/F ratio sensor replacements, and they behave in a similar fashion and report similar voltage readings.

 

[westslope]

@ebenhaber posted on a similar problem in December 2020:

My mistake - actually talking the the mechanic in person he said that the wire had been cut by abrasion because the harness hadn’t been secured and the wires were dangling.

 

[Lowcountry idn]

You in theory could solder it and individually shrink wrap each. If you have the tools and are good at soldering it should hold - but its a bit of an art if you haven't done it much. Use wire that matches what's there (stranded) and has at least the same gauge as what is there or larger. Use thin flux core solder designed for this type of work.

Or you could just get a new sensor since its really not that expensive. My OEM ones were Denso but I would have no issue installing either a Bosch or NTK either. All 3 are OEM suppliers, not jobber parts.

 

[early 2010]

Having tried it before with different O2 sensors, that is not copper wire. It is copper from the plug to the computer. But the plug to the sensor is stainless or something like that. Could not get it to take solder. Crimp connection was the only thing that would work.

 

[Lowcountry idn]

hmmm, must be aluminum, which is really surprising to see on a car. If it is, soldering aluminum is near impossible. Well it can be soldered, but needs special flux that's basically an acid to remove the oxidization, and a pretty hot iron. If it is aluminum I likely wouldn't bother trying.

 

[westslope]

Having tried it before with different O2 sensors, that is not copper wire. It is copper from the plug to the computer. But the plug to the sensor is stainless or something like that. Could not get it to take solder. Crimp connection was the only thing that would work.

Thanks. Good to know. Even up on 6 tonne jack stands, it is hard to see clearly. My go-to digital camera just lost the flash function. The android smartphone is not as good. I mention the cameras because I use digital images to better see and understand what is going on in tough place like under the automobile.

Yesterday, I decided to go ahead and order an NGK replacement O2 sensor from partsavatar.ca. I will try to repair the existing sensor.

Is the crimped connection holding steady?

 

[early 2010]

I guess the crimp worked. Sold that rig 12 years ago. Never heard back that it was an issue.