BMW E90 webasto does not start or shuts off immediately
E90 webasto does not start or shuts off immediately - what is the most common cause?
The most common fault is the circulation pump (auxiliary water pump): when it is stuck or broken, the water does not circulate and the webasto shuts off or does not start. Other causes are a coked burner, a faulty glow plug or flame sensor and fuel supply problems. A weak battery can also cause problems.
What does webasto lockout mode mean?
In lockout mode the webasto does not try to start at all. The cause is often coking, which short drives promote. Removing the fuse does not release the lockout; it is cleared with a diagnostic program. If the burner is coked, the lockout returns immediately until the burner is taken apart and cleaned.
How is a circulation pump fault fixed?
In many cars the pump and the changeover valve are the same part (part number 64126951814), so usually the whole part is replaced. Fault code 00A6D1 points to a short circuit or open circuit in the auxiliary water pump. Listening to the pump and feeling the hoses tells you whether the water is circulating.