Immobilizer does not see the key

Since 1990, all cars have been equipped with an immobilizer. In case of malfunctions in its operation, the car does not start or stalls almost immediately, and the immobilizer key lights up on the tidy. The main causes of malfunctions are a broken key or protection unit, low battery power. To understand why the car does not see the key, and the immobilizer does not function as expected, this article will help.

How to understand that the immobilizer does not work?

The main signs that the immobilizer does not see the key:

• on the dashboard, the indicator of the car with a key or lock is lit or blinking;
• the on-board computer gives errors like “immobilizer, key, secret, etc.;
• when the ignition is turned on, the buzzing of the fuel pump is not heard;
• the starter does not work;
• the starter works, but the mixture does not ignite.

The reasons why the immobilizer does not see the key fall into two categories:

• hardware - breakage of the key chip or the unit itself, broken wiring, dead battery;
• software - the firmware has flown, the key has got rid of the block, the immobilizer glitch.

If there are no direct indications of a failure of the anti-theft lock, an independent check of the immobilizer should be carried out after excluding other possible causes of problems. you need to make sure that the fuel pump, starter relay, contact group of the lock and battery are in good condition.

Why the immobilizer does not see the car key

Understanding why the immobilizer does not see the key will help understanding how it works. A working block of the protective system establishes contact with the key, reads a unique code and compares it with the one stored in memory. When it is not possible to read the code or it does not match what is written in the block, the immobilizer blocks the engine from starting.

The main reasons why the immobilizer does not see the native key, and the ways to solve them, are collected in the table.

Problems	The cause of	What to produce?
breakdowns in the power supply of the engine control unit	Low battery charge	Charge or replace the battery
	Broken wiring	Detect and fix break
	Blown fuse	Inspect fuses, ring circuits for shorts, replace blown fuses
	Bent, detached or oxidized ECU contacts	Inspect the ECU connectors, align and / or clean the contacts
Firmware failure	Corrupted controller software files	Reflash the ECU, register the keys or send off the immobilizer
	Control unit memory failure	Repair (solder the flash and flash the unit) or replace the ECU, register the keys or send off the immobilizer
Physical chip failure and magnetic exposure	Shocks, overheating, wetting of the key	Start the car with a different key, buy and register a new key
	Irradiation of the key with an EMP source	Remove the radiation source, start with another key, replace and register a new key
Battery level drop	Leaving the car with electrical appliances running, battery wear limit	Charge the battery or replace with a new one
Poor connection between antenna and receiver	Damaged or oxidized contacts	Inspect wiring, clean terminals, repair contacts
	Antenna failure	Replace antenna
Disruption of communication between the immobilizer and the ECU	Bad contact, oxidation of connectors	Ring the wiring, clean the contacts, restore integrity
	Damage to the immo block or ECU	Diagnose blocks, replace faulty ones, flash keys or reset the immobilizer function
breakdown in the power circuits of the immobilizer unit	Breakage of wires, oxidation of connectors	Check wiring, restore integrity, clean connectors
Immobilizer does not see the key in cold weather	Low battery	Charge or replace battery
	Faulty immo bypass block in the security system with auto start	Check the immobilizer crawler, the chip installed in it, crawler antennas
	Freezing of electronic components	Warm up the key
Discharged battery in the active key	Battery life expired	Change battery
The immobilizer bypass unit does not work or does not work correctly	Breakdown of the bypass block	Repair or repair bypass block
	See also label in crawler	Fix label

If the immobilizer does not see the key well, the reasons are most often poor contact, mechanical damage to the block or chip, and low supply voltage. You need to pay attention to the listed problems when the car gives an immobilizer error after an accident.

In some cars, after an accident, the security system may block the fuel pump. In this case, the protection must be deactivated. The method for each model is different, for example, on the Ford Focus, you need to press the button for turning on the fuel pump in the niche near the driver’s left foot.

Programmatically disable the immobilizer from the computer

Situations where the immobilizer does not always see the key due to the firmware are rare. Usually if the software fails, then irrevocably. the breakdown is eliminated by rebinding the key or by software disabling the immobilizer.

In cases where the immobilizer does not see the key during the onset of cold weather, owners of Ford, Toyota, Lexus, Mitsubishi, SsangYong, Haval and many others equipped with emergency alarms with auto start in the presence of a crawler may encounter. Therefore, you need to start looking for problems in the bypass block. If the tag is equipped with its own battery, you need to check its charge level, as it drops quickly in the cold.

Most car keys with an immobilizer are passive: they do not have batteries, and they are powered by induction from a coil installed in the area of ​​\uXNUMXb\uXNUMXbthe car lock.

To avoid problems with the immobilizer, it is recommended to follow the following precautions:

• do not disassemble the key, immobilizer and ECU;
• do not throw keys, do not wet or expose to electromagnetic waves;
• use high-quality bypass blocks when installing emergency alarms with auto start;
• when buying a used car, ask the owner for all the keys, a sheet with a written immobilizer code for flashing new ones, and also clarify information about the features of the installed alarm (its model, the presence of an immo bypass, the location of the service button, etc.).

When buying a used car with a single master key, it is not possible to bind new chips to the unit. Only replacing the immobilizer or ECU will help. The cost of these procedures can reach tens of thousands of rubles!

Is it possible to start the car if the immobilizer has flown

If the immobilizer has stopped seeing the key, there are a number of ways to disable the lock. First you should try the spare key. If it is not available or also does not work, other ways to bypass protection will help. The easiest way is with older models without a CAN bus. Launch options are listed below.

Chip in immobilizer key

Using an additional key

If the key from the immobilizer is untied, but you have a spare, use it. Most likely with a different label, the internal combustion engine will start. In this case, you can try to bind the "fell off" base key again using a training one, or buy a new one and bind it.

If there is an alarm with auto start, if the immobilizer does not work, you can start the car with the key from the crawler. You can find it by removing the plastic casing at the ignition switch and finding the antenna coil, the wire from which leads to a small box. In it, installers hide a spare key or a chip from it, which sends a signal to the security unit.

After removing the chip, autorun will not work.

Bypass with jumpers

On cars without a CAN bus, simple immobilizers are used to control on-board electronics, for example, Opel Vectra A, which are easy to bypass. To start such a car you need:

How to disable the immobilizer with jumpers on the Opel Vectra: video

How to disable the immobilizer with jumpers on the Opel Vectra:

1. Find the immo block in the front panel.
2. Find its circuit or disassemble the block and identify the contacts responsible for blocking the fuel pump, starter and ignition.
3. Use a jumper (pieces of wire, paper clips, etc.) to close the corresponding contacts.

Through jumpers, it is also sometimes possible to deactivate the immobilizer on older VAZ models, such as 2110, Kalina and others.

For machines in which the immo block is hardcoded in the ECU firmware, this method will not work.

Crawler installation

If the immobilizer does not see the key, and the above workarounds are not available, you can install an immobilizer crawler. There are two types of such devices:

Immobilizer crawler circuit

• Remote crawlers. A remote crawler is usually used to set an alarm with auto start. It is a box with two antennas (receiving and transmitting), which contains a spare key. How to connect the immobilizer crawler is decided by the car alarm installer, but most often the unit is located in the front panel.
• Emulators. An immobilizer emulator is a more complex device that contains a chip that imitates the operation of a standard protection unit. It connects to the wiring of the immo block and sends unlock signals to the ECU via the CAN bus. Thanks to the emulator, you can start the engine even with a non-chip duplicate key.

In order to do without keys at all, it is the second option that is needed. Such emulators are relatively inexpensive (1-3 thousand rubles), and their installation allows you to start a car without an immobilizer.

The use of crawlers and emulators simplifies the life of the driver, but reduces the degree of protection of the car from theft. Therefore, autorun should be installed only in conjunction with a reliable high-quality alarm and additional protection systems.

Code deactivation of the immobilizer

The answer to the question “is it possible to start the car without an immobilizer, crawler and spare key?” depends on the presence of a special password. The PIN code is entered as follows:

OEM immobilizer keypad in Peugeot 406

1. Switch on ignition.
2. Depress the gas pedal and hold it for 5-10 seconds (depending on the model) until the immobilizer indicator goes out.
3. Use the on-board computer buttons to enter the first digit of the code (the number of clicks is equal to the number).
4. Press and release the gas pedal also once, then enter the second digit.
5. Repeat steps 3-4 for all numbers.
6. Run the unlocked machine.

On some cars, the central lock control button on the remote control can be used to perform the procedure.

Replacing the control unit

If none of the ways to bypass the immobilizer without a key helps, all that remains is to change the blocks. In the best case, you can only replace the immobilizer unit by tying new keys to it. At worst, you will have to change both the ECU and the immo unit. The procedure for connecting and disconnecting the immobilizer depends on the car.

For a number of models, there are firmware with deactivated protection. In them, you can remove the immobilizer lock forever. After flashing the ECU, the engine starts without interrogating the protective unit. But since it becomes much easier to start a car with a non-chip key, it is advisable to use firmware without protection only if there is a good alarm.

What to do if the immobilizer key is untied

If the immobilizer has stopped seeing the key, the system needs to be retrained. To prescribe new or old broken chips, a master key is used, which usually has a red mark. If it is available, you can train the immobilizer yourself if the key has fallen off, according to the standard scheme:

Learning master key with red label

1. Get in the car and close all the doors.
2. Insert the master key into the ignition switch, turn it on and wait at least 10 seconds.
3. Turn off the ignition, while all indicators on the dashboard should flash.
4. Remove the master key from the lock.
5. Immediately insert the new key to be bound, and then wait for the triple beep.
6. Wait 5-10 seconds until a double beep sounds, pull out a new key.
7. Repeat steps 5-6 for each new key.
8. After prescribing the last key, insert the learning master key, wait first for a triple, and then a double signal.
9. Take out the master key.

The above method works on VAZ and many other cars, but there are exceptions. Detailed instructions on how to assign a key can be found in the user manual for a specific model.

On most cars, the binding of all new keys is carried out within the framework of one session, while the old ones, with the exception of the master key, are automatically discarded. Therefore, before you yourself register the keys in the machine immobilizer, you need to prepare both old and new ones.

Frequently asked questions when the immobilizer does not work

In conclusion, we offer answers to the most common questions that appear if the immobilizer does not start, does not see the key, sees it every other time, or all keys with a chip are lost / broken.

• Can the immobilizer work if the key battery is dead?

  Passive tags do not require power. Therefore, even if the battery responsible for the alarm and central locking is dead, the immobilizer will be able to recognize the chip and unlock the start of the internal combustion engine.

• Do I need to use an alarm if there is an immobilizer?

  Immo is not a full-fledged replacement for an alarm, since it only complicates the hijacker's task and does not prevent his access to the salon. The immobilizer does not allow starting, but does not notify the owner of a hacking attempt. Therefore, it is better to use both protective systems.

• How to bypass the immobilizer when setting the alarm?

  There are two ways to bypass the immobilizer when installing an alarm with an autorun system. The first is the use of a crawler containing a spare key or chip. The second is the use of an emulator crawler connected to the immobilizer unit via the CAN bus.

• Why does the immobilizer not see the key if there is an alarm with auto start?

  There are two options: the first - the crawler cannot scan the key normally (the chip has shifted, the antenna has moved out, etc.), the second - the block sees two keys at the same time: in the crawler and in the lock.

• Periodically, the car does not see the immobilizer key, what to do?

  If the immobilizer error appears irregularly, you need to check the electrical circuits, the contacts of the computer and the immobilizer unit, the inductive coil that transmits signals to the chip.

• Is it possible to bind a new immobilizer to the ECU?

  Sometimes the only way to start the car if the immobilizer is broken is to register a new unit in the ECU. This operation is feasible, as well as binding a new controller to an old immobilizer unit, but the subtleties of the procedure differ for different brands.

• Why does the immobilizer work after disconnecting and connecting the battery terminal?

  If the immobilizer light comes on and the car does not want to start without removing the terminal from the battery, you need to check the battery charge. If it is normal, you should look for problems in the wiring. In order to avoid key decoupling and blocking the immobilizer, do not disconnect the battery when the ignition is on!

• How to unlock the immobilizer if there is no key and password?

  In the absence of an associated key and password, unlocking is possible only with the replacement of the immobilizer and flashing the ECU with the binding of a new immo unit.

• Is it possible to disable the immobilizer permanently?

  There are three ways to remove the immobilizer lock permanently: - use jumpers in the immo block connector (old cars with simple protection); — connect an emulator to the connector of the security unit, which will tell the ECU that the key is inserted and you can start (for some modern cars); — edit the firmware or install modified software with the immobilizer functions disabled (VAZ and some other cars). The difficulty of disabling the immobilizer depends on the age and class of the car. This is easier to do on older and budget models than on new and premium ones. If none of the methods described above helped, you should contact a specialist. Auto electricians at dealership service stations, specializing in specific brands of cars, will be able to restore the functionality of the standard immobilizer. Chip tuning specialists will help you remove the blockage forever.