36 · Electrical

Fault diagnosis

Electrical 21B – Anti-theft deviceFault diagnosis

When activated the system automatically carries out a SELF-DIAGNOSIS which indicates possible malfunctions via the flashing of the led

Mode of flashing of led	Meaning	Carry out test
6 Hz, lasting 2.5 secs.	Door/bonnet/boot left open or switch broken Volumetric sensors broken	check correct closure of doors and bonnet/boot. Engage and disengage the system. Count the number of times the led flashes and proceed following the indications given in the table below.
1c Hz, lasting 2.5 secs.	Fault in the electronic circuits of the control unit	replace the control unit N45
No flashing	Malfuction affecting led	J

Also then the system is switched off it will communicate any alarms detected once again by flashing the led:

Number of times led flashes	Components triggering alarm	Carry out test
1 Impulse	Front right-hand door	A
2 Impulses	Front left-hand door	B
3 Impulses	Rear right-hand door	C
4 Impulses	Rear left-hand door	D
5 Impulses	Volumetric sensors	E
6 Impulses	Bonnet	F
7 Impulses	Boot	G
8 Impulses	Interruption in key-activated supply	H
9 Impulses	Interruption in supply to battery	I
10 Impulses	At least three simultaneous causes of an alarm	Rapeat the engagement/disengagement of the system. If necessary carry out all the above tests.

Parts & tools for this job For 1992 Alfa Romeo 155

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