BMW F10 AdBlue system faults
What can cause the AdBlue warning light and the incorrect refill message?
The cause can be bad or expired fluid, a NOx sensor fault or a fault in the urea transfer line. Read the fault codes with a BMW-compatible reader. The fluid freezes at about -11 degrees, and after thawing the fault codes may clear. If the fault does not recur, the yellow light may go out on its own.
What happens if the AdBlue runs out?
Warnings come in good time. When the remaining range reaches zero, the engine cannot be restarted after switching off. The tank holds about 15 litres, and the system is mainly in four-wheel-drive cars.
Is leaked and crystallised AdBlue harmful?
A small crystal deposit by the dosing valve does not necessarily affect operation. AdBlue is alkaline and corrodes copper, zinc and aluminium in particular, and road salt makes corrosion worse. Leaks should be repaired and crystal deposits cleaned off.
What causes a fault in the feed line's heating wire?
Repeated freezing can break the inner tube of the heating wire, so AdBlue leaks between the resistor and the sheath. The resistance changes and the system gives an error code. Replacement is a big job: it requires removing several parts and both fuel tanks.