BMW E65 auxiliary heater (webasto) faults
E65 webasto does not start - what could be the fault?
The webasto is bus-controlled, so it cannot be started by feeding power directly. The cause can be a locked-up control board, a weak or old battery, a missing water valve or the heater's own water pump. First read the fault codes and the heater's voltage and temperature values.
Does replacing the battery help if the webasto does not start?
Sometimes. A new AGM battery has fixed a starting problem in winter, and registering the battery replacement to the car with a diagnostic tool (battery renewal) has got the heater working. Try this before more expensive parts.
Why does the E65 not blow warm air even though the webasto works?
The cause can be the additional circulation valve in the webasto's water line. If flushing the heating system does not find a blockage and warm air still does not come, check this valve. The factory auxiliary heater primarily heats the cabin, not the engine.
What does fault code 009C64 mean in the webasto?
The code means there is no message from the auxiliary heater's receiver (control unit SHZH). So the heater's control board has no bus connection. Have a workshop inspect the wiring and the control unit.