Diagnostic Functions

Diagnostic functions

General
The control module has a built-in diagnostic system, the Volvo on-board diagnostic (OBD) system. This system continuously monitors itself and the input and output signals.

Diagnostic trouble codes (DTCs)
A diagnostic trouble code (DTC) is stored if the control module detects a fault. The control module can store 16 diagnostic trouble codes (DTCs).
If a fault disappears for any reason after the diagnostic trouble code (DTC) has been permanently stored in the control module, information about the fault remains in the control module.

Reading off the Volvo on-board diagnostic (OBD) system
Information about any faults and other information is read off using VIDA which is connected via VCT2000 to the data link connector (DLC) beside the accelerator pedal (AP). VIDA communicates with the control module in a standardized interface.
For more information see Connecting VCT2000 Connecting VCT2000.

Volvo on-board diagnostic (OBD) system
Using VIDA it is possible to:
- read off and erase stored diagnostic trouble codes (DTCs)
- activate components or functions according to certain predetermined patterns
- continuously monitor the values and status of the input and output signals for the signals
- read off the control module identification
- program the control module and ignition key.
The following conditions must be met before the Volvo on-board diagnostic (OBD) system is activated:
- the ignition must be on
- the battery voltage must be normal.

Reading and erasing diagnostic trouble codes (DTCs)
Stored diagnostic trouble codes (DTCs) can be read off and erased using this function.
The on-board diagnostic (OBD) system can identify 16 different faults in the form of diagnostic trouble codes (DTCs). Diagnostic trouble codes (DTCs) can only be erased when all the stored diagnostic trouble codes (DTCs) have been read at least once.

Activating components and functions
This function allows the system components and functions to be activated individually. The ignition must be on for activation to be possible.
For further information about activation, see Activating components and functions Activating Components And Functions.

Reading off input and output signals
Using this function, the values and status of the control module input and output signals can be continuously read off.
For further information about parameters, see Description of immobilizer parameters Description Of Immobilizer Parameters.

Reading off the control module identification
VIDA identifies control modules by reading off a number of codes from the control module memory. This code contains information about the control module P/N and the current software version.

Programming
See the information in Programming and replacing the control module Programming and Replacing the Control Module.