Rear O2 System Fault

[Radar]

Hello everyone,

I'm new to the forum and I've encountered a problem with my new to me RX. It's a 2017 with 1500 miles. I'm getting a rear O2 system fault. It's only showing up when I come to a stop after some steady running on back roads or highway. It hasn't popped up while I'm moving yet. My first instinct is to just replace the sensor but I want to get some feedback from the forum first. I did a search but none of the threads I found on the subject listed a solution.

It's a stock 1190 with stock ECU. It has a 44 tooth sprocket.

Thanks in advance,

Paul

[Cooter]

Thats not an issue I've heard of? Pull up the sensor readings on your dash and see if front/rear are close, then I'd check the circuits at the plug and if (+/-) are right, it's worth throwing an O2 at it? Hard to do ECM diagnosis at it from here. If you do that and it doesn't fix it, I'd call Chaz at Aagard Moto Foundry.

[Radar]

Thats not an issue I've heard of? Pull up the sensor readings on your dash and see if front/rear are close, then I'd check the circuits at the plug and if (+/-) are right, it's worth throwing an O2 at it? Hard to do ECM diagnosis at it from here. If you do that and it doesn't fix it, I'd call Chaz at Aagard Moto Foundry.

HI Cooter. Thanks for the ideas. I didn't realize the O2 outputs were viewable from the display. I believe you have to remove the frame to change the rear O2. I'd rather avoid that if possible.

[Radar]

Just checked the O2 sensor voltages in the driveway. They both seemed to vary from .1 to .8 at idle. Didn't see a significant difference between the front and rear sensors. I'll take it for a ride later and check them at higher rpms.

[Radar]

Does anyone know where the rear O2 sensor connector is?

[Cooter]

About 6" from the sensor. Take off the seat and unbolt the ECM and remove the little black under tray thing. The connector is pretty big actually. Not sure what you're doing, it will give the same reading the ECM see's.

You could probably sneak out the O2 with the airbox out but if your gonna throw parts at it, "removing the frame" is only 6 more bolt after that.

[Radar]

Just want to check the connection. I know it's a long shot.

[Cooter]

Since you are getting a reading on the dash from the ECM, it's working.

Sounds like you have a couple weird issues to figure out. I wouldn't know if they are related but its worth call to Chaz.

[Radar]

So I was able to watch the O2 voltage while it was acting up. 0-.1V while the front was .1-.7V. The rear is also .1-.7 when it not throwing a code. The problem is intermittent. I'm guessing it throws the code when it reads 0V. Only happens at idle.

[Radar]

Sent Chaz an email

[Radar]

Update...................

I was running the stock ECU with a 44 tooth sprocket. I sent the ECU to Tim at IDS to be programed for the correct sprocket and haven't had a single PO151 error since! Not sure what the triggering mechanism for the code was but so far it's gone.

[Keyliesiler]

Update...................

I was running the stock ECU with a 44 tooth sprocket. I sent the ECU to Tim at IDS to be programed for the correct sprocket and haven't had a single PO151 error since! Not sure what the triggering mechanism for the code was but so far it's gone.

I have been at a stand still all season with my rx I have 4 other bikes but it was sad to see her sit all season basically ! I have had her at 3 shops and no one could help me ! I am sending her back to the shop now next week because of this thread !!!! Thank you sooooooo much !

[Radar]

My Rx has been flawless since I had the ECU updated to recognize the 44 tooth sprocket. I hope this works for you.