939003559 - A015 ALARM RINGING WITHOUT A REASON

With the alarm on the alarm cycles are set off without any apparent cause and without any attempts to break into the vehicle.
If it is not possible to stop the siren and deactivate the alarm using the remote control, simply activate the instrument panel by inserting the key in the key recognition device. The system can recognize the transponder and switch off the alarm system in this way.
Results of the tests
0PRELIMINARY CHECKSAll OKProblems encounteredOperation
Check that there is not actually any instrusion in the passenger compartment like an insect that could set off the alarm by moving around or any moving object that could be detected by the ultrasound sensors. Check that the windows are properly shut, especially if there are strong winds.Move on to Step 1Insect in the passenger compartment that is detected by the ultrasound sensors when it moves aroundRemove the cause of the alarm
Vehicle windows open when there are strong windsClose the windows
1CHECK USING DIAGNOSTIC EQUIPMENTAll OKProblems encounteredOperation
Connect the Examiner equipment to the diagnostic socket and check at the Body Computer Node for the presence of any errors in the alarm memoryMove on to Step 2Presence of errorsProceed as instructed by the diagnostic tester
2ANTI-LIFTING/ULTRASOUND PROTECTION CHECKAll OKProblems encounteredOperation
Connect the diagnostic equipment to the diagnostic socket and check at the Body Computer Node in active diagnosis that the anti-lift/ultrasound sensors are working properlyMove on to Step 3Anti-lift/ultrasound sensor faultyReplace the courtesy light module with built-in sensor    Op. 5580E50 ANTITHEFT DEVICE VOLUMETRIC SENSOR R R FOLLOWING ELECTRICAL CIRCUIT CHECK
3PERIPHERAL PROTECTION CHECKAll OKProblems encounteredOperation
Connect the diagnostic equipment to the diagnostic socket and check at the Body Computer Node that the microswitches for the doors, bonnet and boot are working properly. In particular that there are not problems with the doors closed    See Test 70C CHECK ON DOOR LOCK MICROSWITCHES Move on to Step 4
4CHECK USING DIAGNOSTIC EQUIPMENTAll OKProblems encounteredOperation
Connect the Examiner diagnostic equipment to the diagnostic socket and check the condition of the A-Bus serial line between the Body Computer Node and the siren at the Body Computer Node in active diagnosis    See E7015 ALARMMove on to Step 5Fault at A-BUS serial lineRepair the A-BUS serial line    See E7015 ALARM
5SIREN POWER SUPPLY CHECKAll OKProblems encounteredOperation
Check that the siren power supply is correct and check the condition of the connections    See E7015 ALARMEnd of diagnosisSiren power supply not correctRestore the power supply    See E7015 ALARM
Vehicle battery run down (voltage below 3 Volt)Recharge the battery
Body Computer defectiveReplace Body Computer    Op. 5505A32 BODY COMPUTER - R.R