72331 - A20 ALARM SIREN NOT WORKING

The siren is connected to the Body Computer Node via the A-BUS dialogue line. The siren is operated and controlled by the Body Computer Node via a series of encrypted messages;if there is a failure the Body Computer Node detects and memorizes the causes of the malfunction.
STEPOPERATIONS TO BE CARRIED OUTTEST RESULTS
1CHECK USING DIAGNOSTIC EQUIPMENT ALL OKPROBLEMS ENCOUNTEREDACTION
Connect the Examiner diagnostic equipment to the diagnostic socket and check the following at the Body Computer Node in parameters ambient:

  • the presence of the siren
In errors ambient:

  • that there are no faults with the siren
  • that there are no faults with the A-BUS
Move on to Step 1. Siren faulty Move on to Step
2. Fault at A-BUSMove on to Step
3. Siren not present 3. Check the conformity of the vehicle
2ELECTRICAL SYSTEM CHECK.ALL OKPROBLEMS ENCOUNTEREDACTION
Check the siren supply and earth (Wiring Diagram ) E7015 ALARM Move on to Step Fault with electrical equipment Restore the electrical connection (Wiring Diagram ) E7015 ALARM
3ELECTRICAL SYSTEM CHECK.ALL OKPROBLEMS ENCOUNTEREDACTION
Check the continuity and the insulation of the A-BUS line between the Body Computer Node Computer and Siren (Wiring Diagram ) E7015 ALARM Move on to Step Fault at A-BUS line Restore the electrical connection (Wiring Diagram ) E7015 ALARM
4CHECK USING DIAGNOSTIC EQUIPMENT ALL OKPROBLEMS ENCOUNTEREDACTION
Connect the Examiner diagnostic equipment to the diagnostic socket and check the following at the Body Computer Node in parameters ambient:

  • the operation of the siren
Move on to Step The siren is not activated Replace the siren     See in Op. 5580E40 ANTI-THEFT SIREN - R.R.
5CHECK ON CORRECT OPERATION ALL OKPROBLEMS ENCOUNTEREDACTION
Check that the fault is no longer present Fault persists Replace body computer     See in Op. 5505A32 BODY COMPUTER - R.R.