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Audi AdBlue System Fault

Error code: P13DF09 AdBlue system has malfunction

Did you know that the AdBlue system is a complex system of injectors, sensors, pipes and pumps?  Not just an all-singing, all-dancing liquid that saves the planet from nasty diesel emissions.

Here at Fergies German Vehicle Specialists, our team of Audi specialists have the knowledge and experience of working with AdBlue to fully understand the system and all the possible faults within this complex system.

Team that experience with our 15 step evaluation process, and we offer our clients a first time fix every time.  We don’t believe in wasting clients time and money; we want to get the client reunited with their fault free car as quickly as possible.

Audi AdBlue System Fault

So when Mr P brought his Audi A8 to our Audi specialists, we started work immediately to understand what was going on.  The client advised that the AdBlue warning light had appeared on the dash, and when he looked into it some more, he noticed a white crust had begun building upon the engine.

Mr P advised that he had already taken the Audi A8 elsewhere and had had the AdBlue piping replaced. He had had a new pipe fitted to clear up the leak, but the problem continued.   

It carried on leaking, and the warning light was still a daily reminder that his Audi wasn’t working as it should.


Our team of Audi Specialists started by completing a full visual inspection of the engine and confirming that there were no other visible faults with the Audi.  

They then carried out a complete AdBlue system test, using the test set VAS 6532A.  They checked the quality of the AdBlue within the system, and after confirming that it was all ok, the team then looked into the system pressure.  The pressure should be between 4.5 and 5.5 bar, which it was, so the next set of checks was to the injector system.

They checked the injector for leaks, pressure hold, spray pattern, and quality injected. The injector on this Audi A8 failed every test. The system was leaking as a result of too much pressure caused by the injector being blocked solid.

With the injector blocked as it was, the system needed a new injector and seal.  


As an Audi Service garage, we only use genuine Audi parts in our repairs, offering our clients a quality fix and great value for money.

We fitted a new injector and seal to the Audi A8 and repeated the same full system test.  The Audi passed all the tests, so our Audi Specialists took the A8 out for an extended road test to confirm that the AdBlue injector system would work and that the warning lights had gone.  

Everything was working as it should.  Mr P was pleased that our evaluation process made sure we gave the first-time diagnosis & fix to the client, saving him further time and money.


At Fergies, it is essential that we make sure our clients receive that first-time fix, so getting to the root cause of the problem is critical in our approach.  Our 15 step evaluation process means that no stone is left unturned to get a complete understanding of the whole vehicle, not just the fault which leads to a warning light.

Giving our clients a first-time fix is key to making sure that our clients are happy and keep coming back to Fergies for all their Audi service and repair needs.

If your Audi service is due or you have a fault with your Audi, contact us and book in with one of our Audi experts.  You won’t be disappointed.

Fergies – German Vehicle Specialists covering Thatcham, Newbury and surrounding areas.

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