Variant 1
Applies to: APS2
What does Scania APS fault code 4654343 mean?
It is not possible to switch off the compressor and the pressure continues to rise.
What causes Scania DTC 4654343?
Mechanical fault on the compressor relief mechanism or a damaged control line to the compressor. Internal electronic fault in the control unit that was not detected by a diagnostic self-test.
How does the system react?
When the fault is active, the system operates in alternative relief mode. Apart from the changed pressure control, the functionality is unaffected for vehicles with the advanced version. For the high capacity version, only regeneration is adjusted for the increasing pressure. The pressure will continue to increase until the safety valve is triggered.
How to fix Scania APS fault code 4654343?
- Check that the APS unit provides operating air to the compressor.
- Check the control line to the compressor.
- Check the compressor relief mechanism.
- Renew the defective part and clear the fault code.
Variant 2
Applies to: APS2
Detection
It is not possible to switch off the compressor and the pressure continues to rise.
Possible cause
Mechanical fault on the compressor relief mechanism or a damaged control line to the compressor. Internal electronic fault in the control unit which was not discovered by the self-test.
System reaction
When the fault is active, the system operates in alternative pressure control mode.
How to fix
- Check that the APS unit provides operating air to the compressor.
- Check the control line to the compressor.
- Check the compressor relief mechanism.
- Renew the defective part and clear the fault code.
This information is for guidance only. Always follow the manufacturer workshop manual and safety procedures; if in doubt, contact an authorised workshop.