NoX sensor

Faults and Technical chat for the Citroen C4 Cactus
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minimike
Posts: 39
Joined: Thu Feb 23, 2017 6:38 pm

NoX sensor

Post by minimike » Sat Mar 21, 2020 7:22 am

My 1.6 BlueHdi has thrown up the Nox sensor fault code. Originally I cleared it and it stayed off for about 3000 miles but it came back on last week. I removed it and cleaned it/checked for broken wires or anything else obvious but couldn't see anything. I have now ordered a new one which I'm waiting to be delivered.

My question is do I need to involve Citroen after fitting the new one or is it simply a case of clearing the fault codes myself?

It a 66 reg with 85K on BTW.

Cheers, Mike.

Rubik
Posts: 211
Joined: Sat Jun 04, 2016 10:22 pm

Re: NoX sensor

Post by Rubik » Mon Mar 23, 2020 10:23 am

minimike wrote:
Sat Mar 21, 2020 7:22 am
My 1.6 BlueHdi has thrown up the Nox sensor fault code. Originally I cleared it and it stayed off for about 3000 miles but it came back on last week. I removed it and cleaned it/checked for broken wires or anything else obvious but couldn't see anything. I have now ordered a new one which I'm waiting to be delivered.

My question is do I need to involve Citroen after fitting the new one or is it simply a case of clearing the fault codes myself?

It a 66 reg with 85K on BTW.

Cheers, Mike.

Engine fault message appeared the evening before the car was due to go in for its yearly service. I don't cover many miles.

Other than that I thought I was doing well as I was going through a period of no problems with my Friday afternoon car.

It cost a lot of money to put it right. The cheapest part was the sensor, then there was labour and VAT and a download.

Its OK replacing the part but I understand you need the download to reprogram the ECU.

My Citroen agent charged me £58 for the download. The whole job costs me many hundreds.

minimike
Posts: 39
Joined: Thu Feb 23, 2017 6:38 pm

Re: NoX sensor

Post by minimike » Mon Mar 23, 2020 4:49 pm

Thanks for the reply. Did you have the exact same issue? And they had to replace your NoX sensor?

It's our main car and we do >30k per year so I can't really have too many complaints. It has been reliable so far for over 80k.

I've ordered a genuine sensor for £220. So if I have to spend the extra £58 for a reprogram I guess I'll have to be happy with that. I'm just hoping the sensor is the fault like the code reader said.

minimike
Posts: 39
Joined: Thu Feb 23, 2017 6:38 pm

Re: NoX sensor

Post by minimike » Tue Mar 24, 2020 2:02 pm

I have an update.

As it stood the car was showing the EML and also 'UREA' (no countdown) and SERVICE in orange (it was not due a service) The large display read EMiSSIONS FAULT.

Initially it was only the EML. I read the fault code which pointed to the NoX sensor. I cleared the code and the car was fine for around 4k.

The EML returned at this point and then the the urea and SERVICE lights lit up later, then went out for a few miles before reappearing and staying on. At this point I used a generic OBD2 code reader againwhich told me the NoX sensor was not working and that it had lost communication with NoX sensor. I was hoping that the other two lights were connected to the same fault and not something new.The fault codes would not clear.

I then ordered a genuine NoX sensor from eBay, from a supplier in Poland for around £220. This is a saving of around £80 on the UK price.

I fitted it today, cleared all the codes and started the car. The EML light went out straight away and the SERVICE and UREA lights after the car idled for 5 mins.

Fingers crossed now that it is sorted. I am well aware that the lights may return at some point but am reasonably hopeful that they won't. The car is not going to be driven much atm with all the restrictions in place so it may take some time before I know for sure it's cured the problem.

It looks like the part doesn't need any special downloads by Citroen, just the standard code readers seems to do the job.

This is not a hard part to replace by any means either, any half decent DIY enthusiast would manage.

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