[Warning Light] Do fault codes persist?

[leftfootleashed]

Do fault codes need to be manually cleared after the problem has been fixed? Specifically in this case, "anti-pollution faulty".

Had my exhaust replaced by my garage, but they had to do it quickly as I needed the car, and so they weren't able to fix a slight blow from the downpipe/manifold interface (they needed to wait for the cat to cool down, and I didn't have time to wait). They also warned me they had to retap the second lambda sensor, and it might be ok but might need replacing. So there's two possible causes of the fault. I took the downpipe off, cleaned up the mating faces and refitted it tightly and I think I've fixed the blow.

The fault appeared the second time I ran the car after the exhaust was replaced (not on the way back from the garage, but a quarter of a mile into a week long 700 mile trip. ). After that, it came up immediately every time I started up, so I guess it's latched and needs clearing.

I can borrow a diag box off a friend, assuming there's no other way of clearing it?

[Zion]

Yes the code will need to be cleared and if the DPF was near to blocking, then you need to tell the ECU that a new one has been fitted using the replacement parts menu in Diagbox before it will stop pestering you.

[cancunia]

Fault codes do sometimes go away after a 'few' good engine starts without the fault, but the best way to clear them is via an OBD reader or Diagbox. You can clear fault codes with most OBD readers and an app on your phone such as 'Torque'.
Using an OBD reader will also show you if the fault is likely to come back, as it will show as 'pending'.

If you can borrow the Diagbox kit, so much the better.

[leftfootleashed]

Cheers, and thanks for the DPF replacement tip. I'll have a go with my generic OBD reader since I've got nothing to lose and won't be able to get hold of the Diagbox immediately.