Nox sensor replacement

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chrisfozz
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Nox sensor replacement

Post by chrisfozz »

Citroen Relay 2.0 BlueHDi 2016. (my campervan)
Engine light is on.

I had one stored fault, code U029, (lost communication with nox sensor) and one pending fault (same).

I fitted a new nox sensor , plugged in my laptop and got just the one stored fault, U029. I thought this looked good as no pending faults.

Clicked the button to switch off the stored fault but it didn't go off on the dash but the laptop now says no faults.

Can anyone advise what to do next??

many thanks

Chris

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GiveMeABreak
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Re: Nox sensor replacement

Post by GiveMeABreak »

As this is a Blue HDi, you'll have the Adblue system and these can play up - especially in relation to the NOx sensors. Your diagnostic tool probably doesn't cut the mustard as they can't all read the manufacturer specific codes.

As this is likely to be related to the SCR system, I would get the dealer to check it out - as I am aware of some dealers rectifying some issues at a reduced cost if slightly out of warranty. The Adblue tanks on these are sealed, so there is nothing you can do on them - but they should be able to diagnose the specific issue. If you pop your VIN up here (automatically masked, I can see if there are any outstanding after sales campaigns due on your vehicle.

chrisfozz
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Re: Nox sensor replacement

Post by chrisfozz »

thanks for the prompt reply.
vin is VF7**************[VIN obfuscated, can be read by forum staff]

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Re: Nox sensor replacement

Post by GiveMeABreak »

Ok, as I suspected. You have an outstanding after-sales campaign on the Van. When vehicles are not serviced at the dealer, they obviously cannot inform customers of these campaigns as they have no idea who owns the vehicles. These are NOT VOSA safety recalls, but are repairs / fixes / updates to rectify certain known faults. I cannot tell you exactly what the after sales campaign is for - only the dealer can do that. But it won't cost you anything - so I wouldn't hang about.

I would also strongly suggest you don't mention that you have had anything replaced - like the NOx sensor, as they may refuse any work on that basis!

Just ring your nearest dealer and tell them you have been advised of an outstanding aftersales campaign and have your VIN ready. They will advise you further. It may be nothing to do with your problem, but I am aware there have been a lot of problems with vehicles with Adblue systems - especially the older tanks - where they contain metal components and the Urea reacts to them causing corrosion and breakdown, and secondly with the early models also not having vented Adblue caps.

The later Adblue tanks were replaced with plastic internal components to prevent the corrosion. Also the NOx sensors can become corroded and also the heating system for the Adblue pipes to prevent crystallisation.

Let us know how you get on. It may be for something completely different - but see what they say the issue is first and then if it is nothing to do with the SCR system, you may as well ask them to deal with the fault code while it's there.

wheeler
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Re: Nox sensor replacement

Post by wheeler »

After a NOx sensor is replaced the depollution system needs to be re calibrated with diagbox.

The recall will probably be to check the clips that hold the brake pipes to the bulkhead.

chrisfozz
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Re: Nox sensor replacement

Post by chrisfozz »

Many thanks for the above info, i'm thinking about it and as Arnie says, "I'll be back".
Cheers

Chris

chrisfozz
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Re: Nox sensor replacement

Post by chrisfozz »

I have previously checked with a main dealer on the recall issue and it was not relevant.

The current situation as I understand it;-

I have fitted a new nox sensor, so there is a calibration routine that needs to be carried out before the SCR system is serviceable again and I get rid of the EML.

I think my choices are;-

1) Take it to a main dealer and ask them to sort it.
2) Find a garage that knows what they are doing and ask them to do the calibration.
3) Buy a Diagnostic Interface and Diagbox software and do the calibration myself.

At the minute i'm leaning towards option 3. I've looked at how to install Diagbox and am confident I can do that on a Windows XP or 7 laptop.
So, 2 questions;-

I've seen menu options for Programming / Matching, is that where I will to do the calibration using Diagbox, is it difficult?
What software version do I want? V7.83 seem popular.

I'm aware I might be talking out of my hat so any help is greatly appreciated.

Chris

wheeler
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Re: Nox sensor replacement

Post by wheeler »

Its not that hard to find, off the top of my head you do a global test then select injection system > pack repair > replacement parts > De NOx system > replacement of the NOx sensor.
That may not be exact but its along those lines, not hard to find.

Was the recall the brake pipe clips?

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GiveMeABreak
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Re: Nox sensor replacement

Post by GiveMeABreak »

I would forget Diagbox 7.83. You very likely won't be able to sort it out with anything less than V9.68 or thereabouts for this year and system. But do check with your preferred seller before you commit to buying it.

wheeler
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Re: Nox sensor replacement

Post by wheeler »

Ahh, of course 7.83 might be too old to have the functionality of the deNOx system.

chrisfozz
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Re: Nox sensor replacement

Post by chrisfozz »

I tried my local Citroen specialist, Cookswell in Peggswood, Northumberland who offered to to code in the new nox sensor for £30. So i whimmped out on doing the job myself but it's done and the EML is off so i'm happy. Many thanks for the advice offered above, it has been much appreciated.

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Re: Nox sensor replacement

Post by GiveMeABreak »

Not bad for piece of mind - at least it is sorted.