Immobilizer — description, removal and installation (Renault Symbol 2)

General information

Secret access codes are no longer used (i.e. the key does not have a number stamped on it, the car does not have a plate with codes). They are replaced by repair codes reserved for this vehicle.

When carrying out repair work, repair codes can be obtained from the local sales network. To obtain codes, you must know the vehicle identification number (VIN). Spare keys are supplied rie coded. without a number and a metal insert.

A total of four keys can be coded. The functionality of the remote control and battery does not affect the operation of the immobilizer.

If the main key is lost, it is possible to code the spare key (additional) key. It is not possible to replace the immobilizer and the key or the immobilizer and the engine control unit at the same time: these systems are supplied as spare parts without codes.

Already set codes cannot be erased. Authorized key recognition codes change randomly. The immobilizer is activated a few seconds after the ignition is turned off.

Activation of the immobilizer is accompanied by a flashing LED on the instrument panel. The immobilizer has a remote control (in the ignition key) with a microcircuit (A) with access codes. Now the microcircuit is part of the printed circuit board of the control panel.





Signal receiver (immobilizer antenna) is installed around the ignition switch and has a microcircuit with codes for transmitting data to the immobilizer control unit. The antenna does not have its own access codes.

Removal and installation

1. Remove the two parts of the steering column cover.

2. Disconnect the immobilizer antenna connector.

3. Remove the immobilizer antenna from the ignition switch.

4. Installation is carried out in reverse order.





The immobilizer control unit decodes the signal from the ignition key, communicates with the engine control unit, and controls the anti-theft system indicator. The control unit (C) is installed under the instrument cluster.



To open the key cover (without remote control) place the key with the metal insert facing down. Use a small screwdriver to lift the back of the cover (E). Slide the cover in the direction of the arrow.



Opening the cover of the remote control key is done using a small screwdriver inserted into the slot (C).

Immobilizer operation

When the immobilizer is activated, the red LED of the system flashes once per second. After the ignition is switched on, the key code is sent to the immobilizer control unit. If the code is valid, the immobilizer control unit sends a start permission signal to the engine control unit. The immobilizer indicator goes out. If the key code is incorrect, the indicator starts flashing at an increased frequency.

Note: The engine control unit does not store any ignition fault codes in its memory.

If the battery is low, the supply voltage drops during engine start-up, which in turn may cause the immobilizer to be reactivated. If the battery is too discharged, the engine cannot be started even when starting from a tractor.

Indicator operating modes:

• immobilizer activated: indicator blinks once per second;
• key recognized start prohibition removed: indicator goes out after three seconds;
• the key is recognized, but the start prohibition is not removed or there is no connection with the engine control unit: the indicator is constantly on;
• key not recognized: indicator flashes four times per second.

Replacing Immobilizer System Components

New components of the system supplied as spare parts do not have their own codes. When installing on a car, you need to enter access codes. In fact, if you have the correct codes for the old components, it is enough to simply install the new component.

Note: Automatic coding is only possible for a new part. Recoding of an old part is not possible.

When replacing the immobilizer control unit, you must have programmed ignition keys and the engine control unit. Additionally, you must obtain repair access codes. When replacing the engine control unit, you must have programmed ignition keys and the immobilizer control unit. When replacing the ignition key, you must have programmed engine and immobilizer control units. Additionally, you must obtain repair access codes.

Programming procedure using diagnostic equipment

1. Establish a dialogue between the immobilizer and the diagnostic tester.

2. In the Command. Specific command menu, select the SC027 command (immobilizer programming).

3. The display will show the message "remove ignition key", execute the command.

4. The display will show the message "enter code".

5. If the code format is correct, the display will show the message "enter the old programmed key into the lock". Insert the key and turn on the ignition.

6. After completing the programming procedure (a few seconds) the display will show the message "programming completed, start programming keys". Now you can program the ignition keys (no more than four).

7. If the programming procedure is not started within five minutes, the procedure will automatically stop.

Ignition Key Programming Procedure

Note: If there are no valid keys available, programming is performed for all new keys.

Establish a dialogue with the immobilizer control unit. In the Command menu, select the SC028 key programming command.

The tester display will show the message "Remove key from ignition switch".



The tester display will show the message "Enter immobilizer codes". With the ignition off, enter the code (12 hexadecimal digits).

The tester will display the message "Attention, there is no key in the lock. Run the program again to install the key." The tester will display the message "Insert the key into the lock and turn on the ignition."

Algorithm for programming the immobilizer control unit.

The tester will display the message "Programming the 1st key", press the Enter button and remove the key from the ignition. The tester will display the message "Do you want to continue with the next key?" Before programming the next key with this key, turn on the ignition for a few seconds. The display will indicate the serial number of the key being programmed.

Note: The key must either belong to this vehicle or have no codes

The tester will display the message "Writing data to memory". It will take a few seconds to write the data.

When the recording is interrupted, the following message will appear: "Procedure interrupted. Attention, old keys have the same codes, new keys already have a code and cannot be used on another car."

Programming the engine control unit

After replacing the engine control unit (comes without access codes) turn on the ignition for a few seconds. After turning off the ignition, the immobilizer will be activated and send codes to the engine control unit.