Immobilizer System

The immobilizer system prevents the car from being used if a non Volvo original key for that vehicle is used to start the car. The identity of the key is checked electronically when the key is inserted. On cars with the keyless system it is checked by the keyless vehicle module (KVM). If the key is not approved, the steering wheel lock will not be unlocked and the engine will not start. The customer will not notice the function of the system as long as a valid key is used an no fault occurs.

Remote-controlled immobilization 

Applies for the English, Dutch, and Belgian market. A special version with stricter requirements is available for the Brazilian market. Applies from and incl. structure week 201020.

On certain markets there is a function for remote-controlled immobilization and mobilization. The purpose of the function is to nullify the vehicle's programmed keys in case the vehicle is stolen, for example. The vehicle can be immobilized and mobilized either using Volvo On Call service center or via diagnostic commands in VIDA (Volvo scan tool). For certain markets vehicles can only be mobilized by Volvo On Call service center.

If the vehicle is running when immobilization is requested, the vehicle is immobilized at the next start attempt. Central electronic module (CEM) can, in certain markets, request immobilization if the module detects that Phone module (PHM) does not answer to communication.

The function remote-controlled immobilization is diagnosed by Central electronic module (CEM). Immobilization and mobilization of vehicles via diagnostic commands takes place via Phone module (PHM).

Deactivation (only cars without the keyless entry) 

When the key is inserted in the ignition switch, the key blade acts on the key-in switch. The key-in switch then forwards 12V from the battery to the central electronic module (CEM) and to the communication circuit in the start control module (SCU). The central electronic module (CEM) then activates the fuel pump (FP). When the signal is received by the central electronic module (CEM), it sends this command to the start control module (SCU) instructing it to check the key. The start control module (SCU) activates the antenna ring and reads off an identification code from the key transponder. This code is transmitted to the central electronic module (CEM) and compared with the codes programmed in the central electronic module (CEM).

If the vehicle has an Alcohol Analyzing Start Inhibitor (option 2009-), an approved breath test must be performed in order for the Alcohol Analyzing Start Inhibitor handheld unit to send an approved signal to the Central electronic module (CEM) via the Remote Receiver Module (RRX).

If the key is approved, the central electronic module (CEM) transmits a command to the steering column lock module (SCL) to unlock the steering wheel lock. The vehicle cannot be started before the spring bolt in the steering column lock module (SCL) is in the unlocked position. The immobilizer system contains several safety functions to ensure that the steering wheel lock does not lock while driving.

When the steering wheel lock is unlocked, the communication between the central electronic module (CEM) and engine control module (ECM) is checked. This is to ensure that the correct codes are programmed into both control modules. The engine control module (ECM) also checks the identity of the brake control module (BCM) by reading off its serial number. This number is compared with the number programmed into the engine control module (ECM). If these checks are completed satisfactorily, the engine control module (ECM) activates the ignition system. The engine control module (ECM) also transmits a command to the central electronic module (CEM) to allow the fuel pump (FP) to continue to run. If a fault should occur or a check is not approved, the engine control module (ECM) instructs the central electronic module (CEM) to deactivate the fuel pump (FP). The engine control module (ECM) also checks the other parameters covered by the start inhibition function. If all conditions are met, the engine control module (ECM) activates the relay for the starter motor. The engine can then be started.

If any of the above steps should fail, the engine will not start and a message will be displayed in the driver information module (DIM).

The immobilizer system has built-in diagnostic test modes (DTM) to ensure that the engine can be restarted after unintentional stops.

Passive deactivation and start (only cars with the keyless locking system) 

The key-in switch is activated when the starter button is pressed in. The keyless vehicle module (KVM) then scans for a passive key inside the vehicle. At the same time, the central electronic module (CEM) transmits an encrypted request to the keyless vehicle module (KVM). This request is responded to only if an approved passive key has been registered. If a key is found, the keyless vehicle module (KVM) checks that the key is approved. If this is the case, the keyless vehicle module (KVM) transmits a response to the central electronic module (CEM) indicating that the key is approved.

If a passive key is not registered, the keyless vehicle module (KVM) will transmit a negative response to the central electronic module (CEM). The central electronic module (CEM) will then transmit a request to the start control module (SCU) instead to search for a transponder. The central electronic module (CEM) will approve the key if a transponder is found.

If the key is approved, the central electronic module (CEM) transmits a command to the steering column lock module (SCL) to unlock the steering wheel lock. The vehicle cannot be started before the spring bolt in the steering column lock module (SCL) is in the unlocked position. The immobilizer system contains several safety functions to ensure that the steering wheel lock does not lock while driving.

When the steering wheel lock is unlocked, the communication between the central electronic module (CEM) and engine control module (ECM) is checked. This is to ensure that the correct codes are programmed into both control modules. The engine control module (ECM) also checks the identity of the brake control module (BCM) by reading off its serial number. This number is compared with the number programmed into the engine control module (ECM). If these checks are completed satisfactorily, the engine control module (ECM) activates the ignition system. The engine control module (ECM) also transmits a command to the central electronic module (CEM) to activate the fuel pump (FP). The engine control module (ECM) also checks the other parameters covered by the start inhibition function. If all conditions are met, the engine control module (ECM) activates the relay for the starter motor. The engine can then be started.

If any of the above steps should fail, the engine will not start and a message will be displayed in the driver information module (DIM).

The immobilizer system has built-in diagnostic test modes (DTM) to ensure that the engine can be restarted after unintentional stops.

Activation 

The immobilizer system is activated when the ignition is switched off. The engine cannot be started when the system is activated. The engine control module (ECM) then deactivates the ignition system and the relay for the starter motor. The central electronic module (CEM) deactivates the fuel pump (FP) and sends a command to the steering column lock module (SCL) to lock the steering wheel lock. As a safety precaution, the steering wheel lock cannot be locked before the central electronic module (CEM) receives an indication that the vehicle is stationary and the engine off. The engine control module (ECM) transmits the status of the engine to the central electronic module (CEM). The central electronic module (CEM) uses the signals on the controller area network (CAN) from the brake control module (BCM) or transmission control module (TCM) to check that the vehicle is not moving.