Complaint/Problem	Possible cause	Test step/Remedy 1)
Preglow indicator lamp does not light with glow/starter switch ON, engine can be started.	Preglow indicator lamp.	Instrument cluster (A1)
Preglow indicator lamp does not light, engine can not be started.	Preglow control module (N14/2). Voltage supply to preglow control module (N14/2) is missing.	23 15.0
Preglow indicator lamp lights up while driving for approx. 1 minute.	Open circuit of glow plug	23 16.0
Preglow indicator lamp lights up while driving or lights intermittantly.	Short circuit in preglow control module (N14/2).	23 15.0
Preglow indicator lamp lights up while driving or lights intermittantly.	Communication fault between engine control module (IFI) (N3/7) and preglow control module (N14/2).	23 14.0

1) Observe Preparation for Test, see 22 .

Note regarding preglow current circuit: A melt-down fuse is installed for each individual glow plug in the preglow control module (N14/2). With a short circuit in the glow plugs or the electrical wiring to the glow plugs, the current circuit is interrupted. The preglow control module (N14/2) must be replaced after the short circuit is eliminated.