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. The control module can store up to 10 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 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 275 different faults in the form of diagnostic trouble codes (DTCs).

This function can also be used to read off whether the fault is still present (permanent) or whether it has now ceased (intermittent) after the diagnostic trouble code (DTC) has been stored.

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:
- the status of the relay for extended X supply. The relay controls the power supply for the following functions: parking heater, power driver's seat and "post drying" for the air conditioning (A/C) system. The relay is activated in key positions I, II and III when the drivers door is opened (10 minutes), driver's door is closed and key position 0 (1 minutes) and when one of the above functions is activated
- the status of the relay for extended X2 supply (AUT). Controls the power supply to the gear selector module (GSM). The relay is activated in key positions I, II, III, 0 or out for 10 seconds
- the status of the relay for the park neutral position (PNP) switch
- the status of the relay for the starter motor (activation signal from the central electronic module (CEM) to the relay)
- the status of the relay to raise the rear left-hand window. The relay is only active when the window lift mechanism is operated via the switch in the driver's door
- the status of the relay to lower the rear left-hand window. The relay is only active when the window lift mechanism is operated via the switch in the driver's door
- the status of the relay to raise the rear right-hand window. The relay is only active when the window lift mechanism is operated via the switch in the driver's door
- the status of the relay to lower the rear right-hand window. The relay is only active when the window lift mechanism is operated via the switch in the driver's door
- the status of the relay for the child lock (blocks operation of the rear window lift mechanisms). Note that when the function is activated, (i.e. the LED lit), the relay which supplies the rear window lift mechanisms is not activated. The read off gives the status of the relay
- status of the relay for high beam
- status of the relay for low beam
- status of the spot lamp relay
- status of the parking lamp relay
- status of the relay for the daytime running lamps
- status of the relay for the front fog lamps
- status of the relay for the windshield wipers, off or on
- status of the relay for the windshield wipers, high speed
- status of the relay for the washer motor
- status of the relay for the headlamp washer
- status of the relay for the horn
- status of the power supply (S-, X-, 15-, 50- and 30-supply)
- status of the key position
- status of the L signal (from the generator (GEN)). Ignition on ~0V, engine running ~1v
- status of the confirmation from the gear-shift position sensor about whether start (starter motor relay activated) is possible
- the status of the frequency signal from the engine control module (ECM) for the fuel pump (FP) relay
- the status of the windshield washer reservoir level
- the status of the windshield wipers
- the status of the driver's door (open or closed)
- the status of the passenger door (open or closed)
- the status of the left rear door (open or closed)
- the status of the right rear door (open or closed)
- the status of the tailgate (open or closed)
- the status of the lock switch for the driver's door (from the driver door module (DDM))
- the status of the lock switch for the passenger door (from the passenger door module (PDM))
- the status of the lock switch for the left-hand rear door
- the status of the lock switch for the right-hand rear door
- the status of the signal from the relay switch for the fuel pump (FP)
- the status signal from the supplemental restraint system (SRS) module indicating whether the Airbag is OK
- the status of the switch for the hazard warning signal flasher
- the status of the button lamp for the hazard warning signal flashers
- the status of the key ring lighting
- the status of the indication LED for the alarm
- the status of the fuel pump (FP)

NOTE: The seat belt switches are connected to the Supplemental Restraint System Module (SRS) on model year 2003 and onward. They cannot then be read from the Central Electronic Module (CEM).

- the voltage of the seat belt switch, driver's side
- the voltage at the seat belt switch, passenger side
- output, pulse width modulated signal to the courtesy lighting
- speed signal (for accessories). If the car is raised for this read off, ensure that the wheels are stationary when the gear selector is moved to position P (automatic transmissions). Note that diagnostic trouble codes (DTCs) may be stored in the ABS system if the front wheels are stationary and the rear wheels rotate
- the status of the pulse width modulation (PWM) signal for headlamp beam height control
- the status of the pulse width modulation (PWM) signal from the left-hand Xenon lamp (65%-90%)
- the status of the pulse width modulation (PWM) signal from the right-hand Xenon lamp (65%-90%)
- the fault status for the xenon lamp
- the status of the infotainment relay.

Activating components and functions
This function can be used to activate components and functions which affect the outputs of the central electronic module (CEM).

The following components can be activated:
- deactivation of the relay for extended power supply
- activating the relay for extended X2 supply
- activating the relay for the park neutral position (PNP) switch
- activating the relay to raise the rear left-hand window
- activating the relay to lower the rear left-hand window
- activating the relay to raise the rear right-hand window
- activating the relay to lower the rear right-hand window
- activating the relay for high beam
- activating the relay for low beam
- activating the spot lamp relay (accessory)
- activating the relay for the parking lamps
- activating the relay for the daytime running lamps
- activating the relay for the front fog lamps
- activating the relay for the windshield wipers off/on
- activating the high speed windshield wiper relay
- activating the relay for the front washer motor
- activating the relay for the headlamp washer
- activating the relay for the horn
- activating the frequency signal from the engine control module (ECM) for the fuel pump (FP) relay
- activating the speed signal (for accessories)
- activating the signal to the switch for the hazard warning signal flashers. To switch off the hazard warning signal flashers, they must be activated and reset again. The function is switched off if the button in the car is pressed once
- activating the key ring lighting (the key ring lighting does not light if the car is locked. The window can be open however, to allow communication with the data link connector (DLC))
- activating the signal for the alarm LED
- activating the pulse width modulated signal for the courtesy lighting
- activating the relay for preheating the leak diagnostic pump
- activating the infotainment relay.

Reading off and programming data
This function allows programmed data to be read off or data such as customer parameters to be programmed in.

NOTE: If possible, all data must be read out from the control module before replacement. After replacement the relevant data must be programmed into the new control module.

Customer parameters can be programmed for approach lights, seat heaters, post drying and daytime running lamps.

Seat heaters: First read off the parameters programmed in the central electronic module (CEM). For example 37C. Then enter the temperature desired by the customer, for example 41C. After programming, the new parameters must be saved to the control module memory. The following values can be entered: 0, 10C, 28C, 30C, 31C, 32C, 33C, 34C, 35C, 36C, 37C, 38C, 39C, 40C, 41C, 43C. The left and right-hand seats are programmed individually. The customer can select high or low.

Approach lights: First read off the parameters programmed in the central electronic module (CEM). For example 30 seconds. Then enter the time desired by the customer, for example 90 seconds. After programming, the new parameters must be saved to the control module memory. The following values can be entered: 0, 30, 60 and 90 seconds.

Post drying: First read off the parameters programmed in the central electronic module (CEM). Reply for example the function is not set. Then enter if the customer wants post drying (the function is set). After programming, the new parameters must be saved to the control module memory. The following values can be entered: Off or on.

Daytime running lamps: First read off the parameters programmed in the central electronic module (CEM). For example daytime running lamps off. Then enter whether the daytime running lamps are to be on (daytime running lamps on). After programming, the new parameters must be saved to the control module memory. The following values can be entered: Off or on. There are two versions of OFF. Low beam can be on in all light switch positions except P. An adjustable position for low beam can also be selected.

Reading off the control module identification
VADIS/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.