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How to fix the AdBlue error on an Audi A4 B9

Model: Audi A4 B9 - Years 2014-2024
Part: AdBlue warning light

In this video, we can see how to fix the AdBlue malfunction on an Audi A4 B9: a warning appeared on the dashboard informing us that within a thousand kilometers, the engine will not start if we do not solve the AdBlue problem. This message can be caused by many issues, so the best thing to do is to connect a tester to the EOBD socket and check what comes out. In this case, it was the error P2E800 indicating low additive pressure. In fact, the system operates at 5 Bar, and at the time the error was detected, the pressure was between 0.5 and 0.6 bar. The issue was therefore the pump that was unable to generate the correct pressure. The pump cannot be blocked, because otherwise it would not even generate this pressure; so we check the electrical contacts and wiring of the pump to verify that there are no pressure leaks through these deteriorated components; then we must check the level of the additive in the AdBlue tank. It indicated that the tank was 75% full, but by emptying the tank, only a few drops of additive were removed, so the problem was a faulty sensor, which was promptly replaced.

Posted on 9 March 2025 by ScegliAuto

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by ScegliAuto

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