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)
If the control module detects a fault a diagnostic trouble code (DTC) list is sent from the additional heater module to the central electronic module. The heater can identify up to 25 faults.
The diagnostic trouble codes (DTC) are stored in the central electronic module. If for some reason a fault disappears after the diagnostic trouble code (DTC) has been permanently stored, information about the fault is stored in the central electronic module.

Reading off the Volvo on-board diagnostic (OBD) system
Information about faults and other data can be read off using the VIDA PC connected to the data link connector (DLC). The VIDA PC communicates with the control module via a standardized interface.

Volvo on-board diagnostic (OBD) system
With the VIDA PC it is possible to:
- read off and erase stored diagnostic trouble codes (DTCs)
- continuously monitor the values and status of the input and output signals for the signals
- activate certain functions
- read off the control module identification.
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 25 different faults in the form of diagnostic trouble codes (DTCs).
Diagnostic trouble codes (DTCs) can only be erased when all diagnostic trouble codes (DTCs) have been read at least once. Diagnostic trouble codes (DTCs) for the heater are stored in the central electronic module.

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.
The following parameters can be read off:
- failed start attempt, Heater
- successful start attempt, Heater
- overheating incidents, Heater
- engine coolant temperature, value
- battery voltage, value
- additional heater status, value
- Extended X-supply, status
- glow plug, status
- glow plug grade, value
- water pump, status
- combustion fan, actual value
- combustion fan, calculated value
- combustion fan PWM, value
- fuel pump frequency, value
- fuel level, status
- heater operation time, value
- supply voltage to components, status.

Activating components and functions
With this function the components and functions in the additional heater system can be activated.
The following components can be activated:
- the additional heater
- the water pump
- the combustion fan
- the glow plug
- the fuel pump
- component supply voltage.

Note! It is important that only the ignition is on in order for the heater to start.

Reading off the control module identification
The control module can be identified by reading off a code from the control module memory.
The code contains information about the control module's:
- hardware P/N (control modules without software)
- hardware serial number (control modules without software)
- software P/N
- P/N diagnostic software.