Both NOX sensors need replacing - advice!
Both NOX sensors need replacing - advice!
Author
Discussion

sg0102

Original Poster:

20 posts

176 months

Monday 24th November
quotequote all
Hi all,
Owner of a 2019 Peugeot 5008 1.6 Diesel GT Line here, currently on 66k miles.
Have had a repeated engine warning light appearing, with Ad Blue error and countdown clock of mileage before impossible to start.

Garage just reset it originally, they now believe that both NOX sensors need replacing, at a cost of £1k.

I phoned one garage for an alternative quote, which he wouldn't give me over the phone, but raised a degree of caution that if both sensors need replacing, it may be part of a broader issue?

My current plan is to sell the car in the next 9-12 months, so very nervous of being stung with ongoing big costs!

So, any help would be greatly appreciated.

a) Does this sound right as a resolution ?
b) does this cost feel appropriate (indpendent garage)
c) Should I worry about broader issues, and if so, over what timeframe?

Thanks in advance!
Steve

paul_c123

1,470 posts

13 months

Monday 24th November
quotequote all
There's about 10,000 ECU fault codes, half of which would light up the EML, so its impossible to say what it is simply from the symptoms you describe. It needs diagnosing properly. Since a garage has had hands on it, and I'm just sitting at the other end of the internet, not really possible to help further without more information.

You could always get your own code scanner, scan the car and let us know the code(s).

stevemcs

9,804 posts

113 months

Monday 24th November
quotequote all
Usually its just the one, nevr had to replace both.

sg0102

Original Poster:

20 posts

176 months

Monday 24th November
quotequote all
Yeah, not totally sure why it’s both! Considering disabling the EGR now as am planning selling soon and just can’t afford the cost right now.

Megaflow

10,795 posts

245 months

Monday 24th November
quotequote all
sg0102 said:
Yeah, not totally sure why it s both! Considering disabling the EGR now as am planning selling soon and just can t afford the cost right now.
Disabling the EGR will make no difference. NOx sensors are part of the ad-blu system, the first measures the NOx to work how much ad-blu to inject and the second confirms it worked.

sg0102

Original Poster:

20 posts

176 months

Monday 24th November
quotequote all
Ah, maybe I’m taking about the wrong thing? Is it ECU remapping I mean? Or is that the same!?

GreenV8S

30,993 posts

304 months

Monday 24th November
quotequote all
sg0102 said:
Ah, maybe I m taking about the wrong thing? Is it ECU remapping I mean? Or is that the same!?
No offense meant, but if you were planning to do this yourself then I suggest you give up on that idea, based on the level of understanding you have currently. If you're planning to pay somebody else to do it then I suggest the only sensible approach is to pay somebody to fix your actual problem. If you try to diagnose it yourself and use the interweb to figure out what might fix it and tell them to do that, I'm sure they'll happily take your money but you've no reason to expect it will actually fix the problem and no come-back against them if it doesn't. From your replies I don't get the impression you want to throw money at it speculatively.

sg0102

Original Poster:

20 posts

176 months

Monday 24th November
quotequote all
Fair comment mate!

If I step away from trying to use terminology, I was under the impression there was something you can do - not clear on what - which makes adblue / emissions monitoring redundant. Given that’s what the NOX sensors, I believe are there to do, it made sense in principle to negate the need for them.

But I am likely wrong as I am definitely not Pistonhead.

Megaflow

10,795 posts

245 months

Monday 24th November
quotequote all
I believe the ad-blu system can be deactivated

stevemcs

9,804 posts

113 months

Monday 24th November
quotequote all
Adblue and nox usually go together, ECU measures what NOX goes into the exhaust, what comes out and then injects Adblue in to lower the NOX emissions when required.

The adblue tank is the most common failure on these followed by the injector (have a look and see if its corroded) it sits in the downpipe and leaks. NOX fault codes can be as a result of the system not working and not always a sensor fault. The nox sensors can sometimes be seen as lambda sensors.


Like this …



Edited by stevemcs on Monday 24th November 20:49

E-bmw

11,836 posts

172 months

Tuesday 25th November
quotequote all
sg0102 said:
I was under the impression there was something you can do - not clear on what - which makes adblue / emissions monitoring redundant. Given that s what the NOX sensors, I believe are there to do, it made sense in principle to negate the need for them.
Yes, there are but it is not legal to disable/bypass any part of an emissions control system.

As was said above, get a second opinion and get the problem fixed before it becomes a real problem.

stevieturbo

17,902 posts

267 months

Tuesday 25th November
quotequote all
E-bmw said:
Yes, there are but it is not legal to disable/bypass any part of an emissions control system.

As was said above, get a second opinion and get the problem fixed before it becomes a real problem.
or get rid of the car.

E-bmw

11,836 posts

172 months

Tuesday 25th November
quotequote all
stevieturbo said:
E-bmw said:
Yes, there are but it is not legal to disable/bypass any part of an emissions control system.

As was said above, get a second opinion and get the problem fixed before it becomes a real problem.
or get rid of the car.
Indeed. wink

ComStrike

461 posts

113 months

Friday 5th December
quotequote all
Megaflow said:
I believe the ad-blu system can be deactivated
Which then clogs the DPF as it stop regenerating, then it destroys the turbo & pumps more exhausts gases back into the crankcase .....
Yeah .. great idea

Megaflow

10,795 posts

245 months

Friday 5th December
quotequote all
ComStrike said:
Megaflow said:
I believe the ad-blu system can be deactivated
Which then clogs the DPF as it stop regenerating, then it destroys the turbo & pumps more exhausts gases back into the crankcase .....
Yeah .. great idea
I didn't say it was a good idea, I just said it could be done.

Sardonicus

19,276 posts

241 months

Friday 5th December
quotequote all
Have you checked the Ad-Blue level? is the tank full or been run low? because you will get odd errors if the system runs low from what you describe to comms issues when all it needs is a NOX system re-boot/initialisation with a suitable diagnostic tool I know because ive done them previously yes NOX sensors can give issues but not always the fault of the Ad Blue system failure/errors/countdown, got to say I find PSA / Fords software often irritating for reasons like these

Edited by Sardonicus on Friday 5th December 13:09