S60 L5-2.4L VIN 64 B5244S6 (2003)
The Active On-demand Coupling (AOC) can be described as a hydraulic pump.
The basic pressure is generated by the electronic feed pump. This pressurizes the annular pistons with oil so that they are pressed against the cam disc
via rollers. The annular piston generates a working pressure which is led to the operating piston via the pressure valve. This pressure creates a fixed
connection between the input and output shafts. The maximum pressure is limited by the pressure limiting valve. The difference in speed between the
input and output shafts is in proportion to the oil pressure fed to the annular pistons. A large difference between the input and output shafts results in
high oil pressure to the annular pistons. If the input and output shafts are at the same speed, the oil pressure to the annular pistons is less. The oil
pressure at the multi-plate clutch is regulated by the control valve. The axial solenoid controls the control valve. A closed control valve gives
maximum pressure to the multi-plate clutch, resulting in maximum power transmission. An open control valve gives minimum pressure to the
multi-plate clutch, resulting in limited power transmission.
The accumulator maintains the basic pressure in the system. The oil filter keeps the fluid clean by filtering dirt and small particles which could damage
the system.
Diagnostic functions
General The control module has a built-in diagnostic system, Volvo Diagnostic, which continuously monitors internal functions as well as input and
output signals.
Diagnostic trouble codes (DTCs)
A Diagnostic Trouble Code (DTC) is stored if the control module detects a fault. Should a fault disappear for any reason after being permanently
stored in the control module as a Diagnostic Trouble Code (DTC), the information remains stored in the control module.
Reading and erasing Diagnostic Trouble Codes (DTCs)
Stored Diagnostic Trouble Codes (DTCs) can be read off and erased using this function.
Diagnostic Trouble Codes (DTCs) can only be erased once all the Diagnostic Trouble Codes (DTCs) have been read off at least once.
Reading off input and output signals
This function can be used to continuously read off the status of the control module's input and output signals.
Reading off the control module identification
VADIS identifies control modules by reading off a number of codes from the control module memory.
The codes contain information about the control module:
-
hardware P/N (control module without software)
-
hardware serial number (control module without software)
-
software P/N
-
diagnostic software P/N.
Downloading software and replacing the control module
New software for the Differential Electronic Module (DEM) can be downloaded. When ordering software, the hardware and the software in the car
are compared to the data in the Volvo central database.
If the comparison is OK the software is downloaded to the control module. If the comparison between the car and Volvo central database is not OK,
the database is updated with the car configuration. When this is complete the software is downloaded.
The control module is integrated in the coupling unit for the Active On-demand Coupling (AOC). If the control module is replaced, the control
valve/axial solenoid and oil pressure and temperature sensor must also be replaced.
