Diagnostic Functions

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. A fault which is detected in the most recent operating cycle is defined as permanent. Other faults are defined as intermittent. If for some reason a fault disappears after the diagnostic trouble code (DTC) has been permanently stored in the control module, information about the fault is stored in the control module.

Reading off the Volvo on-board diagnostic (OBD) system
Information about faults and other data can be read off using VIDA. VIDA communicates with the control module in a standardized interface.

Volvo on-board diagnostic (OBD) system
Using VIDA 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.
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 values and status of the control module's input and output signals.
The following parameters can be read off:
- Engine coolant temperature sensor.The coolant temperature in the heater
- Overheat protection thermostat.The coolant temperature in the heater
- Flame sensor.The temperature at the flame sensor
- Modulation degree glow plugs.Reading off the degree to which the glow plug is activated
- Fuel pump frequency.Reading off the frequency of the fuel pump
- Water pump.On: Water pump activated. Off: Water pump deactivated
- Fuel level, status.Reading off the lowest permitted quantity of fuel to allow the heater to start
- Lowest permitted battery voltage.Reading off the lowest permitted battery voltage to allow the heater to start
- Highest permitted battery voltage.Reading off the highest permitted battery voltage to allow the heater to start.

Activating components and functions
The components and functions in the engine coolant heater system can be activated using this function.
The following components can be activated:
- Combustion fan.Activating the combustion fan. A "buzzing" sound can be heard from the combustion fan when it is activated
- Glow plugs.Activating the glow plug
Caution! Do not activate this function for more than 10-20 seconds.

- Fuel pump.Activating the fuel pump. A "buzzing" sound can be heard from the fuel pump when it is activated
- Water pump.Activating water pump. A "buzzing" sound can be heard from the water pump when it is activated
- Heater.Activating the heater procedure.

Note! The ignition must be on for activation to occur.

Reading off the control module identification
VIDA 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.