System Description

Alarm system with integral Central Locking System
The 911 Carrera (993) is fitted with a diagnosable alarm system that incorporates the central locking feature, the delayed switchoff of the interior lights and an anti-drive-off feature.

The alarm system is activated by:
1. Locking a door.
2. Locking one of the door locks three times in rapid sequence.

After arming the alarm system, the operation of all actuation circuits is checked. If no fault is detected, this condition is indicated by rapid flashing of the alarm readiness lamps (approx. 10 seconds).

After approx. 10 seconds all actuation circuits are armed. Slow flashing of the alarm readiness lamps indicates this condition.

If a fault condition is detected, the LEDs do not flash during the check period (approx. 10 seconds).

This may be due to the following fault conditions:
- Vehicle doors not closed
- Vehicle doors not locked
- Hood not closed
- Luggage compartment lid not closed
- Glove compartment lid not closed
- Rear parcel shelf not closed (if fitted)
- Radio not fitted correctly

Only those activation circuits that are not faulty are armed after the check has been terminated. A fault condition is displayed by double flashing after the check has been terminated. If an alarm has been triggered, this is also indicated by double flashing.

Three different alarm types preadjusted according to the country specifications are provided in the control unit. When replacing the control unit, the country-specific coding must be reestablished with System Tester 9288.

Central Locking System
The Central Locking System covers the driver and passenger doors. The key may be used to lock and unlock the driver and passenger doors. The locking status of the vehicle is indicated by the flashing code of the alarm readiness lamps.

When the ignition is switched off, the central locking button in the center console may be used to lock the doors only. Wit the ignition on, it may be used to lock and unlock the doors. When the driver's door is open, the doors cannot be locked.

Time-delay circuit of the interior lights
The interior lights are no longer controlled directly via the door contacts. The interior lights are switched on:
1. By unlocking the doors.
2. By locking the doors.

The lights continue to be lit for approx. 20 seconds.

The interior lights are switched oft (doors closed):
1. When the ignition is switched on.
2. When the doors are locked.

Anti-drive-off feature
The anti-drive-oft feature is activated when the alarm system is armed. If an alarm is triggered, terminal 15 for the DME control unit is interrupted and the ignition and injection systems are disabled.