NOx Sensors

Faults and Technical chat for the Citroen C4 Cactus
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Posts: 2
Joined: Sun Jun 14, 2020 12:03 pm

NOx Sensors

Post by cjtc4c » Thu Jul 30, 2020 11:59 am

Hi All,

I have had my Cactus 5 months and low and behold - the Engine Management light and Emissions faults have come on the dashboard! The fault codes are:-
U029D - Lost comms with NOx sensor A
P2200 - NOx sensor circuit Bank 1 Sensor 1

I read these codes with my own code reader but i am unable to delete them, so initially I am thinking one of two things...
1. Its a faulty NOx sensor - around 400-500 fitted
2. The UREA pump is faulted - around 1000+ fitted (if I'm lucky!)

So disappointed I didn't read upon the Adblue system before I bought the car.

My question is - how many NOx sensors are there on the C4 Cactus? I have located and checked the one in the centre of the car underside (the one fitted to the exhaust pipe), but is there one further towards the engine? I have looked online and everyone only mentions the one I've already checked. The codes I have say Sensor A (Sensor 1), so I'm guessing there is another one?

Any help would be appreciated. Its booked into the garage next week, but I would like any info. if possible?

Thanks in advance.

Posts: 139
Joined: Tue Mar 26, 2019 3:43 pm

Re: NOx Sensors

Post by routemaster1 » Thu Jul 30, 2020 6:46 pm

Usually when the Adblue pump fails, you get the 'Urea' warning light on the dash. Hopefully it will be a sensor (expensive enough). Have you any warranty?

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