2015 AUDI SQ5 Adblue fault, bit of advice needed.

Trevorleach · 2026-03-01T08:47:10+0000

Wife bought this car a few months back, few miles after we left the dealer the engine light came on!
Back home and plugged in, code came up for reductant sensor, cleared it down as garage had already told us they had changed an adblue pipe and or sensor, so I just assumed they had not cleared or road tested it enough.
Fast forward to one week ago and up comes the engine warning light with the exact same code stored.
What I would like to know is, is the sensor likely to be at fault, is it an **** to change, or should I just get it mapped out?

bert · 2026-03-01T08:52:56+0000

I'd be taking it back to the dealer to sort as it should be under warranty still

daedalusminos · 2026-03-01T08:58:08+0000

The date would suggest a historical (but maybe still relevant) fault. Have you consulted Ross Tech wiki for correct clearing procedure?

Moose McAlpine · 2026-03-01T09:02:30+0000

Trevorleach said:
What I would like to know is, is the sensor likely to be at fault, is it an **** to change, or should I just get it mapped out?

It's part of the Adblue unit/module, with the pump, heater, level sensor, etc. I had the same fault on my A6 (same engine) and the module was ~£800.

I had it mapped out, and the power bumped up while i was there.

reb78 · 2026-03-01T11:13:26+0000

A friend of mine had a refused recovery by the RAC recently because they could see the ad blue on his van had been mapped out when they plugged it in. Just mentioning in case mapping this tech out causes problems that you don't yet know about!

Trevorleach · 2026-03-01T16:33:33+0000

daedalusminos said:
The date would suggest a historical (but maybe still relevant) fault. Have you consulted Ross Tech wiki for correct clearing procedure?

Sorry that is the picture from when we first got the car, the other pic I took a few days ago is almost the same word for word

Trevorleach · 2026-03-01T17:22:57+0000

reb78 said:
A friend of mine had a refused recovery by the RAC recently because they could see the ad blue on his van had been mapped out when they plugged it in. Just mentioning in case mapping this tech out causes problems that you don't yet know about!

Another reason to not use the AA!