Both NOX sensors need replacing - advice please!

smg0102

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

Bigwheels1111

Where to start.
Count down has nothing to do with Nox sensor.
Which idiots told you this.
Halford, Kwikfit etc.

Do you have a cheap OBD2 scanner ?.

I have a 5008, 2016,  1.6 bluehdi.

The countdown is for adblue. Have you topped it up ?. From memory it must be a 10L top up to put out light.
There is or was a fault with the tanks pump, plus the injector into the exhaust leaks.
I know this as my tanks pump went.
Replaced under extended warranty.

Only main dealers can fit new tanks as needed to be programmed by them.
Well that’s what I found out after doing my due diligence.

My Nox sensor warning came on a few times 3 or 4 year back, I scanned the car with an OBD2 fault code reader.
Cleared the code and all was good.

I used Yeomans Peugeot Littlehampton.
They were brilliant, Took in car, scanned it, checked injector etc. Found tank was issue.
Ordered new one and fitted it.
Fixed the problem first time.

1, Get OBD2 scanner and scan car for codes. 
2, Top up adblue 10L, only buy from shop where adblue is on display in the shop not outside and sun damages it.
3, Pay for Peugeot to scan car if countdown continues.

https://www.youtube.com/shorts/CMPEJpERBkM

Goudy

I suspect you are suffering from the famous Adblue pump, tank, injector failure that plagues these models.

The tank, pump and electronics are one unit and the PCB that controls it is part of the tank and prone to contamination by the Adblue.

Just search the internet for Peugeot or Citroen Adblue fault.

Peugeot issued a TSB regarding the problem, it's basically a replace and reset notice.

It's not a cheap part but I believe a few companies are refurbishing tanks for around a third of the price as the parts inside have now become available. I presume someone has copied the parts so they are refurb'd with aftermarket parts.
See Turbo Tec's website.

smg0102

Thanks both. 

So this is starting to stress me out!

Sequence of events is this:
Engine warning light comes on
Then additional light stating "emissions failure"
Then a countdown clock came on a day or so later stating "this car will be impossible to start in xxx miles" 

I've taken it to my local independent mechanic who told me that both NOX sensors need replacing to fix this, at a cost of £1k. I've used these guys for years and trust them, but given the sizeable cost just want to do my diligence before I spend the money. From what I'm hearing and reading, it doesn't sound clear if that is a reliable diagnosis, and/or could be the first of a chain of events incurring more cost in time. Which, given I want to sell in the next 9 months or so, is forcing me to really consider options! 

Adblue is all topped up and this error is still present. 

"I suspect you are suffering from the famous Adblue pump, tank, injector failure that plagues these models" - curious if this could be the current cause of the error messages, or something that could come subsequently? 

Thanks all
Steve 

smg0102

Sounds like deleting Ad Blue may be the way forward...

GunJack

smg0102 said:

Sounds like deleting Ad Blue may be the way forward...

When I asked a senior mechanic at our local Peugeot dealer about an adblue fault on a 3008 1.6 his advice was (on the QT) to get the car remapped to take the adblue out of it totally...fraction of the price and never have an adblue issue again (unless the ECU needs totally reloading from scratch then you'd have to remap again). Not quite word-for-word but that was what he was saying..he also mentioned the fact that adblue faults are notorious for reappearing in quite short order even after they've been "fixed" - his emphasis not mine.

Goudy

smg0102 said:

Thanks both. 

So this is starting to stress me out!

Sequence of events is this:
Engine warning light comes on
Then additional light stating "emissions failure"
Then a countdown clock came on a day or so later stating "this car will be impossible to start in xxx miles" 

I've taken it to my local independent mechanic who told me that both NOX sensors need replacing to fix this, at a cost of £1k. I've used these guys for years and trust them, but given the sizeable cost just want to do my diligence before I spend the money. From what I'm hearing and reading, it doesn't sound clear if that is a reliable diagnosis, and/or could be the first of a chain of events incurring more cost in time. Which, given I want to sell in the next 9 months or so, is forcing me to really consider options! 

Adblue is all topped up and this error is still present. 

"I suspect you are suffering from the famous Adblue pump, tank, injector failure that plagues these models" - curious if this could be the current cause of the error messages, or something that could come subsequently? 

Thanks all
Steve 

To fit a NOx sensor shouldn't be £1000.
You can buy a Bosch one for around £150 and fitting is fairly easy.
One end is screwed into the exhaust after the DPF then the rest is fitted within a rubber cover and plugged in under the car.

Your engine and emission warning, plus the countdown on the dash even after you have topped up the Adblue is suggesting the Adblue tank/pump/PCB is knackered.
It's very very common on these diesel engines.

You need to
A: Find out what you are getting for your £1000.
Is it just a NOx sensor.
B: Read up on the Pug/Citroen Adblue tank/pump/PCB problem.

Bigwheels1111

My 5008 had its first mot in 2019.
Every year the emissions level was 0.01 or 0.02 depending on how warm the car was.
With the adblue system off line my reading was 0.00.
So adblue does what ?.

Goudy

Bigwheels1111 said:

My 5008 had its first mot in 2019.
Every year the emissions level was 0.01 or 0.02 depending on how warm the car was.
With the adblue system off line my reading was 0.00.
So adblue does what ?.

The MOT test doesn't test for Nitrogen Oxides so there is no surprise the test reading aren't affected by disabling the Adblue system.

It tests for Carbon Monoxide (CO) and Hydrocarbons (HC)

The test equipment will also calculate how close the fuelling is in relation to the ideal fuel to air ratio (stoichiometric).
As it's not an actual reading it per say, it's just a calculation, so it's expressed as Lambda.

It's not easy to test NOx levels as they will change depending on drive cycle, so they are generally tested before the engine makes it to market under "lab" conditions.

Generally with throttle on, NOx production is usually quite low.
With throttle off and the engine pumping basically nothing but air, the combustion chamber temps sky rocket and NOx proliferates. 

Just for interest the Euro 6 NOx emission level for a diesel car is 0.080 g/km and 0.060 g/km for petrol.

This is why the exhaust recirculation valve is designed to open and close and Adblue is introduced only at certain points in the drive cycle rather than all the time.