939003556 - A020 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 by means of a series of coded messages; in the case of a failure the Body Computer node detects and memorizes the causes of the malfunction.The siren is equipped with a battery whose charge is guaranteed in the presence of a +15 supply from the ignition with the alarm system switched off and is managed by the actual siren; the activation/end of charge command is given by the Body Computer
Results of the tests
1CHECK USING DIAGNOSTIC EQUIPMENTAll OKProblems encounteredOperation
Connect the diagnostic equipment ot the diagnostic socket and check for the presence of the siren at the Body Computer Node in the parameters ambientMove on to Step 2Siren not presentCheck the conformity of the vehicle
2SIREN ELECTRICAL EQUIPMENT CHECKAll OKProblems encounteredOperation
Check that the power supply for the siren is correct and check the continuity and insulation for the A-BUS serial line between the Body Computer Node and the siren by carrying out the    See Test 5580EB SIREN FUNCTIONAL TESTMove on to Step 3
3CHECK USING DIAGNOSTIC EQUIPMENTAll OKProblems encounteredOperation
Connect the Examiner diagnostic equipment to the diagnostic socket and check the following at the Body Computer Node in parameters ambient. the correct activation of the siren. the condition of the A-Bus serial lineMove on to Step 4The siren is not activatedReplace the sirenSee Test 5580E40 ANTI-THEFT DEVICE SIREN - R+R
Serial line brokenRenew serial line    See E7015 ALARM
4CHECK ON CORRECT OPERATIONAll OKProblems encounteredOperation
Check that the fault is no longer presentEnd of diagnosisThe fault persistsReplace Body Computer    Op. 5505A32 BODY COMPUTER - R.R