Engine management light on after NOx sensor replaced.

Faults and Technical chat for the Hyundai Tucson
Post Reply
Mr.C
Posts: 17
Joined: Thu Apr 27, 2023 9:12 am

Post by Mr.C »

My car is a Hyundai Tucson 2.0 CRDi 48v MHD premium SE.
Engine management light came on on 1st January.
My code reader would not read the code so I went to my mechanic to get it read and cleared.
I went to my local Hyundai dealership and got it booked in for the sensor to be replaced. Apparently a common fault.
Unfortunately it has come back on. The dealership reset it again and I drove back home (20 miles) but next morning on drive to work it came back on again after about driving for 10 minutes.
Any ideas what else could be the issue?
Any help much appreciated.

20250105_125118.jpg

User avatar
PhilHornby
Posts: 548
Joined: Fri Mar 03, 2023 6:04 pm
Location: North Devon

Post by PhilHornby »

Mr.C wrote: Mon Jan 27, 2025 12:49 pm I went to my local Hyundai dealership and got it booked in for the sensor to be replaced. Apparently a common fault.
Any ideas what else could be the issue?
Logically :-
  • New sensor is defective as well
  • There is a wiring fault
  • ECU is defective
  • Water ingress into connector (corrosion)
  • Contaminants in exhaust gas (oil etc)
  • Soot build-up, as well, apparently - though highly unlikely in this case
I'm not familiar with NOx sensors (or diesels really), so I don't know if they are easy to 'bench-test'.

The dealership should be able to monitor it working (or not) on the car - sometimes sensors that don't work, will initially cause a 'pending fault' to be logged. If it's pending for long enough, it becomes a 'hard fault' and the MIL illuminates.
N Line S Hybrid (HEV).
23 plate - built Nov '22
Mr.C
Posts: 17
Joined: Thu Apr 27, 2023 9:12 am

Post by Mr.C »

Dropped car off this morning at Murley Hyundai Stratford this morning. Rang them back just now hoping I would get my car back this evening. They have now said its the other Nox sensor before the cat.
Hopefully this will resolve this issue. Strange now the other sensor is now faulty.
User avatar
PhilHornby
Posts: 548
Joined: Fri Mar 03, 2023 6:04 pm
Location: North Devon

Post by PhilHornby »

You live and learn... I didn't expect there to be two of them, but makes sense to have one either side of the cat.
N Line S Hybrid (HEV).
23 plate - built Nov '22
Post Reply

  • You may also be interested in...
    Replies
    Views
    Last post