O2 sensor problems and MIL 142/143

Woe unto you that bought the first model year of a major remake, perhaps this section can help address any 2014 and later model Ural "imperfections". Here's a special section for folks with the latest rigs to discuss 2014 and later model-related topics such fuel injection, 3-wheel disc brakes, hydraulic steering dampers, spin-on oil filters and other anomalies that don't belong on true Russsian motorcycle ;-P We've gone from using big hammers and greasy wrenches to needing computers and Ouija boards in order to fix our rigs.
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Please keep this section specific to issues pertaining to 2014 and later models such as fuel injection, sidecar and rear disc brakes and so forth. Ask general or non-2014 and later specific questions in the main Hammerin' & Wrenchin' section.
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Ostwind
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O2 sensor problems and MIL 142/143

Post by Ostwind » Sun Mar 31, 2019 2:55 pm

Hello Ural-community,
first of all I have to apologize: English is not my first language and that’s why my grammar/spelling could be weak. I hope you understand everything (:

So I had this crazy dream about owning my own Ural and later to drive it around Europe with my girlfriend after I finish my studies. Well, I managed to get my hands on a 2016 Gear-Up in the end of the last year with only 80 kilometers. It was love at first sight and I got no problems the first 500km. While the ride back from the nearest Ural dealer in heavy rain after an inspection the MIL came up and went off and came up again (and so on). Like there would be a loose contact somewhere. Code sequence were mostly 142 (O2 sensor circuit failed high) and 1 or 2 times 241 (O2 sensor circuit failed low).
After I got home I disconnected both O2 wire-connectors. Water came out of left one (MIL Code 142), the right one (MIL Code 241) was fine. I tried to dry both as good as possible. Then after a few days, I connected everything back together. Because I found some of some (I think) electrical connector grease in the right connector I got some electrical connector spray for the left one too. It seems like the water flushed the old grease out. After a short test ride afterwards the MIL didn’t came up again. Shortly after this, I took my rig on a longer trip again. After 5-10 minutes riding the MIL came up again but I couldn’t check it because it went off again too fast. However I managed to get the code again, and who would be surprised it was 142 (O2 sensor circuit failed high), the right one were fine. The MIL came and went off during the ride over and over again. I could easily ride 1 hour without it and suddenly it were back again on for 20 minutes before it went off again.
Now after a week I wanted to get back to this mystery and this time the MIL were lighting up even before I started the bike. The MIL code is now 143 (O2 heater open or short to battery).

I read in another topic, that I have to change my O2 sensor but does it suit my problem too? Would it help to try out some electrical connector grease (instead spray) for the left connector again? Why did it work in the first place?

Hope you can help me
Greetings from Germany
Ural Gear-Up 2016
Germany

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Mr Wazzock
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Re: O2 sensor problems and MIL 142/143

Post by Mr Wazzock » Sun Mar 31, 2019 3:21 pm

Yes someone else on this forum had this happen too, water in the sensor, and had to get a new sensor I believe. I think the 'high' error refers to the internal heater, but only guessing. If so it means heater element is non-conductive, not working.
Mike H
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(aka Oranzhevaya Opasnost, "The Orange Peril")

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Re: O2 sensor problems and MIL 142/143

Post by Albuquralque » Sun Mar 31, 2019 6:34 pm

Swap the sensors with each other. If mil follows the sensor, then you need a new sensor.
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Re: O2 sensor problems and MIL 142/143

Post by Kaliram » Mon Apr 01, 2019 11:24 am

Did you buy the rig from a dealer, and Is it still under warranty? ...ie, 2 new O2 sensors might be had just for the asking...
Current ride: 2016 Ural Gear Up ("Shanti ")
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Ostwind
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Re: O2 sensor problems and MIL 142/143

Post by Ostwind » Mon Apr 01, 2019 12:49 pm

Thanks for the replies guys.

I will try to swap the sensors in the next days and will post the results here again.
I didn’t bought the rig from a dealer and it’s not under warranty anymore – sadly a new oxygen sensor cost about 90 € here.
I sealed the upper, external part of each connector (where the wires go in) with silicone, so that water can’t flush them that easily anymore. I didn’t know that the Ural is so much afraid of water from above or is it an individual problem?
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Re: O2 sensor problems and MIL 142/143

Post by Ostwind » Wed Apr 03, 2019 10:37 am

As feared, after I swapped the sensors with each other, the MIL followed the sensor. So I already ordered a new one and talked with one of our dealers here. It seems like that this happens now and then and there is nothing you can do about it besides to avoid driving in the rain.
At least I try to cover both sensors more, to avoid another failure. The dealer also told me that the 2019 Urals will have similar problems because their o2 sensors are also not well protected.

Anyway thanks for your feedback.
Greetings
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Re: O2 sensor problems and MIL 142/143

Post by hotflash44 » Wed Apr 03, 2019 11:51 am

Ostwind wrote:
Wed Apr 03, 2019 10:37 am
As feared, after I swapped the sensors with each other, the MIL followed the sensor. So I already ordered a new one and talked with one of our dealers here. It seems like that this happens now and then and there is nothing you can do about it besides to avoid driving in the rain.
At least I try to cover both sensors more, to avoid another failure. The dealer also told me that the 2019 Urals will have similar problems because their o2 sensors are also not well protected.

Anyway thanks for your feedback.
Greetings
have to think that there is more to the failure than just water,as all cars now have o2 sensors located under the car near the header exhaust pipe. never heard of a issue with these o2s. :? :cheers:
2016 gear up asphalt grey, name Seryy Medved ,Air America CIA circa 1967/8 Vung Tau Viet Nam USS Tutuila ARG-4 (AND JUST A TOUCH OF AGENT ORANGE!)

Ostwind
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Re: O2 sensor problems and MIL 142/143

Post by Ostwind » Wed Apr 03, 2019 12:25 pm

Well, according to the dealer the problem, with the o2 sensor the Ural have, is that their sealing could fail after some time. The rubber gasket inside the sensor which should protect it from water is exposed to high temperatures for long periods. That could cause low-porosity and water (after heavy rain) could get more easily inside of the sensor causing failures. But it only could … that’s why most of us don’t have problems with them so far.
Another weak spot is the connector from the sensor to the electric circuit. Water can get there too and causing MIL codes (see my problems or other MIL codes related to o2 sensor here in the forum). That’s why everybody should check those connectors from time to time too, to make sure no humidity got there. :cheers:

I am not well informed about o2 sensors in cars but I think the hood of the car protects it from the rain, right?
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Re: O2 sensor problems and MIL 142/143

Post by rivers » Wed Apr 03, 2019 12:55 pm

Dielectric grease is your friend.
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Re: O2 sensor problems and MIL 142/143

Post by Mr Wazzock » Wed Apr 03, 2019 6:58 pm

hotflash44 wrote:
Wed Apr 03, 2019 11:51 am
have to think that there is more to the failure than just water,as all cars now have o2 sensors located under the car near the header exhaust pipe. never heard of a issue with these o2s. :? :cheers:
They also have a belly pan aka underbody shield that prevents spray getting into the engine bay. So in fact the engine compartment should be completely weather proofed. This is because of all the electronics and things like O2 sensors.

:D

Anyway for Ural, I'm thinking it might not be a bad idea to have a spare sensor in reserve.
Mike H
2016 Ural cT, in glorious terracotta
(aka Oranzhevaya Opasnost, "The Orange Peril")

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