| STEP | CHECK TO BE PERFORMED | RESOLUTION IF THE CHECK IS NOT OK | 
|---|
| 1 | Press the START/STOP button and turn off the engine.Reconnect all the disconnected components.Turn off all the electrical users.Insert a new fuse F11 in the engine compartment junction unit and check it does not blow.Move on to Step 3 | Move on to Step 2 | 
| 2 | If necessary, repair errors in the wiring between the engine compartment junction unit and spark plug control unit    See E5050  DIESEL ENGINES ELECTRONIC MANAGEMENT  The test can be considered over | Replace the glow plug preheating unit    Op. 5520C20  HEATER PLUGS CONTROL UNIT - R.R | 
| 3 | Press the START/STOP button.Check that fuse F11 cuts in | A temporary current overload has occurred in the circuit behind fuse F11. connect the electrical connectors for the junction unit. | 
| 4 | Press the START/STOP button.Disconnect the harness from a spark plug.Fit a new fuse F11 and check it does not blow.Reconnect the spark plugs and disconnect another, repeating the test until all the spark plugs have been checked. | Replace the spark plug that does not trigger the fuse    Op. 5520C10  HEATER PLUGS - R+R | 
| 5 | If necessary, repair the faults in the wiring between the spark plug control unit and the glow plugs    See E5050  DIESEL ENGINES ELECTRONIC MANAGEMENT | Replace the glow plug preheating unit    Op. 5520C20  HEATER PLUGS CONTROL UNIT - R.R |