If a fault occurs when processing a service function, the following causes are possible:
| 1 | Faults in the system. | First, correct the faults. Note: Also watch out for error messages while the service function is running. | 
| 2 | The instructions have not been followed precisely. | Especially for learning procedures, it is required that the instructions regarding the vehicle condition (for example ignition off for 10 seconds, start engine) be followed precisely. |