Published: 23.03.2026
This Audi Q2 came into us with warning lights showing on the dashboard. The customer wasn’t sure what the issue was, but the lights indicated a fault within the emissions system. As with many modern diesels, problems with the AdBlue system can quickly lead to further warnings or even restricted vehicle performance if left unresolved.
We started with a full diagnostic scan, which flagged a fault with the AdBlue heater system. This system uses two heaters to keep the AdBlue fluid at the correct temperature. After further testing, we identified two separate issues: a faulty AdBlue heater relay and a broken wire in the circuit supplying power to heater number two.
During testing, we fitted a new relay, but noticed heater two still wasn’t receiving power. Using the diagnostic tool, we confirmed the issue by temporarily introducing a good wire into the circuit, which immediately triggered the system as expected. This confirmed a wiring fault rather than a component failure alone.
We replaced the faulty relay unit and carried out a proper repair to the damaged wiring. Once completed, we re-tested the system to ensure both heaters were working correctly and all warning lights were cleared.
The Audi is now running exactly as it should, with the AdBlue system fully operational and no faults present.