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, CEM
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 "after blow" 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 minute) 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 windscreen wipers, off or on
- status of the relay for the windscreen 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 windscreen washer reservoir level
- the status of the windscreen 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.

Reading off parameters, Immobilizer
- ID CODE RECEIVED
Indicates whether the central electronic module (CEM) has received a key code (Transponder ID code). This applies whether the key is stored as an approved key or not. YES or NO. However, the key must be of the correct type - intended for this type of Volvo.
- ID CODE STORED
ID CODE STORED Indicates whether the last received key code (transponder ID code) is stored as an approved key code in the central electronic module (CEM) memory. YES or NO.
- RANDOM CODE TO TP
Indicates whether the central electronic module (CEM) is transmitting a random code to the key which presupposes that the key code is stored. SEND or DO NOT SEND.
- RESPONSE FROM TP
Indicates whether the central electronic module (CEM) is receiving a response from the key (via the antenna ring) which presupposes that the key code is stored. YES or NO. YES is also displayed for a key belonging to another car of the same type, with the same key ID but a different security code.
- TP STATUS OK
Indicates whether all of the following conditions are fulfilled: 1) Key code (transponder ID code) is stored. 2) The key has the car's security code (the key belongs to the car). 3) Communication (random code and response) is OK. YES or NO.
- KEY TYPE
Indicates whether the ignition key used is a MASTER KEY or a SERVICE KEY
- KEY NO.
Indicates which of the vehicle's keys is in the ignition switch. Each key programmed into the central electronic module (CEM) is given a serial number from 1 to 6. NO. 1 - NO. 6.
- NUMBER OF KEYS
Indicates how many keys (key codes) are stored in the central electronic module (CEM) memory, 1-6. A maximum of six keys can be stored.
- IMMO MODE
Indicates the mode of the immobilizer in the central electronic module (CEM), NORMAL or PROGRAMMABLE. In NORMAL it is not possible to change the content (add/erase key codes) in the immobilizer. In PROGRAMMABLE mode the immobilizer can be programmed (add/erase key codes). In this mode the engine cannot be started.
After a programming has been carried out, VIDA returns to NORMAL mode.

Hint: If communication problems occur during programming, the central electronic module (CEM) remains in PROGRAMMABLE mode.
To correct this, remove fuse 11C/32 from the fusebox in the passenger compartment and reinstall it so the central electronic module (CEM) returns to NORMAL mode again.

- ECM DATA RECEIVED
Indicates whether the Control area network (CAN) signal containing Immo ECM data transmitted is received within a given (maximum) time. This signal is transmitted by the engine control module (ECM) to the central electronic module (CEM) on the high speed network, when the ignition is switched on. YES or NO
- ECM START SIGNAL
Indicates whether the Control area network (CAN) signal transmitted by the engine control module (ECM) to the central electronic module (CEM) on the high speed network after an IMMO CHECK is completed, when the ignition is switched on, allows the engine control module (ECM) to be start (POS) the engine or not (NEG). The following conditions must be met before the engine control module (ECM) will allow the engine to be started. The transponder check must have been successful (the key code, transponder ID, is stored and the security codes for the key and the central electronic module (CEM) correspond). The immobilizer check must have been successful (the codes in the central electronic module (CEM) and the engine control module (ECM) correspond).
- IMMO RELAY STATUS
Indicates the status of the immobilizer's request to the starter motor relay. If the immobilizer permits the relay to connect the starter motor, START POSSIBLE is displayed. IF not, START NOT POSSIBLE is displayed.

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 windscreen wipers off/on
- activating the high speed windscreen 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 heater: First read off the data that is programmed in the central electronic module (CEM). Answer, for example, 37C. Then enter the temperature desired by the customer, for example 41C. After programming, the new data must be saved in the control module memory. The following values can be programmed in: 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 and there are two settings that can be selected by the customer, high or low.
Approach lights: First read off the data that is programmed in the central electronic module (CEM). Answer, for example, 30 seconds. Then enter the time desired by the customer, for example 90 seconds). After programming, the new data must be saved in the control module memory. The following values can be programmed in: 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 data that is programmed in the central electronic module (CEM). For example, daytime running lamps off. Then enter if the vehicle is to have daytime running lamps (daytime running lamps on). After programming, the new data must be saved in the control module memory. The following values can be programmed in: Off or on. There are two versions of off. Dipped headlamps can be switched on in all light switch positions apart from the P position. The dipped headlamp beam can also be adjusted.

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.