Troubleshooting Central Warning System


The central warning system monitors the following 1 9 7 8 Models functions in the car.

Warning Porsche 928

Any deviation from specified condition or a defect will be displayed by the central warning lamp flashing or coming on, depending on priority, the acknowledgement button and the pertinent indicator lamp. Beginning with 1979 models the acknowledgement button comes on together with the central warning lamp.

3 — Brake circuit failure

4 - Brake fluid level

7 — Coolant temperature

9 - Washer fluid level

11 - Stop lights

12 - Tail lights

Beginning with 1 9 79 models

The central warning unit contains a "bulb check" function to check the light bulbs. All indicator lamps, the central warning lamp and the acknowledgement button lamp must come on after turning on the ignition.

Voltage is supplied to the central warning unit via term. 50 while starting the engine and cancels the "bulb check" function. All indicator lamps go out except for the stop light indicator (goes out when operating brake pedal first time) and parking brake indicator (when parking brake is applied).

Monitoring the tail lights and stop lights is accomplished with a bulb check control unit, which together with the central warning unit will activate the pertinent indicator lamp when a bulb is defective or a wire has a break.

Config Warning 737 300

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Types of Defects

1982 Porsche 928 Central Warning Unit

The following defects could occur in the central warning system.

1. Check lamp(s) do not come on when checking light bulbs.

2. Indicator lamp on continuously, instead of flashing (for functions 1 — 4).

3. Indicator lamp not on, even though monitored CWL = Central Warning Lamp function is not okay.

ABL = Acknowledgement Button Lamp IL = Indicator Lamp (or Sign Light)

4. Indicator tamp on, even though monitored function is okay.

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