The modern car key has reached a new level in terms of ease of use and security. It allows only a certain person to gain access to the car and start the engine.
There are also simplified versions of these devices. But regardless of this, most car keys are necessarily equipped with batteries.
And these batteries tend to run out. Their charge drops below the minimum level, and the key stops functioning. To fix this, you need to replace the battery correctly and in a timely manner.
Types of car keys
If you have problems with the ignition, you shouldn’t immediately paint terrible pictures in your head. Perhaps the problem is the key, and then everything will be limited to replacing the battery. In the case when it is present.
First of all, you need to understand which version of the key is used for a particular car - there are several varieties:
- Classic. Both the chip and the microcircuit are absent in this version. Is there a power supply? No. And why does it need a metal blank with threads?
- Service. This option has a more complicated device - a transponder chip is available. But the functionality is limited to simply opening the lock. There is no need to wait for remote operation; in most cases there is no battery;
- Having an electronic transmitter and a rotating mechanism. The case contains a microcircuit and a transponder that allows you to control the lock at a certain distance. The battery is, of course, installed;
- Equipped with a discharge mechanism. Here you need to take a closer look at the product - it can be either with or without a battery;
Smart keys. Present in cars where there is no standard ignition switch - the “start-stop” button works instead. There is a battery - a must.
Is it possible to start a car if the immobilizer has gone off?
If the immobilizer no longer sees 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 methods of bypassing the protection will help. The situation is easiest with older models without a CAN bus. Options for launching them are outlined below.
Chip in immobilizer key
Using an additional key
If the immobilizer key has become loose, but you have a spare one, use it. Most likely the engine will start with a different mark. In this case, you can try to re-bind the “fallen off” main key using a training key, or buy a new one and bind it.
If you have an alarm with auto start, if the immobilizer does not work, you can start the car with the key from the lineman. You can find it by removing the plastic trim from 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, autostart will not work.
Bypass using 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 run such a machine you need:
How to disable the immobilizer using jumpers on an Opel Vectra: video
How to disable the immobilizer using jumpers on an Opel Vectra:
- Find the immo block in the front panel.
- Find its circuit diagram or disassemble the unit and, by testing, identify the contacts responsible for blocking the fuel pump, starter and ignition.
- Use a jumper (pieces of wire, paper clips, etc.) to close the corresponding contacts.
Using jumpers it is also sometimes possible to deactivate the immobilizer on older VAZ models such as 2110, Kalina and others.
For cars where the immo block is hardcoded in the ECU firmware, this method will not work.
Installing the crawler
If the immobilizer does not see the key, and the above bypass methods are not available, you can install an immobilizer bypass. There are two types of such devices:
Immobilizer bypass circuit
- Remote crawlers . A remote crawler is usually used to install an alarm system with auto start. It is a box with two antennas (receiving and transmitting), which contains a spare key. How to connect the immobilizer bypass 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 simulates the operation of a standard protection unit. It connects to the wiring of the immo block and sends unlocking signals to the ECU via the CAN bus. Thanks to the emulator, you can start the engine even with an unchiped duplicate key.
In order to do without keys at all, you need the second option. Such emulators are relatively inexpensive (1-3 thousand rubles), and their installation allows you to start the car without an immobilizer.
The use of crawlers and emulators makes life easier for the driver, but reduces the degree of protection of the car from theft. Therefore, autostart should only be installed in conjunction with reliable, high-quality alarm systems and additional protection systems.
Coded immobilizer deactivation
The answer to the question “is it possible to start a car without an immobilizer, a lineman and a spare key?” depends on the presence of a special password. The PIN code is entered as follows:
Standard immobilizer keyboard in Peugeot 406
- Turn on the ignition.
- Depress the gas pedal and hold it for 5–10 seconds (depending on the model) until the immobilizer indicator goes out.
- Use the on-board computer buttons to enter the first digit of the code (the number of presses is equal to the number).
- Press and release the gas pedal again, then enter the second digit.
- Repeat steps 3–4 for all numbers.
- Start the unlocked car.
On some cars, the central locking control button on the remote control may 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. At best, you can only replace the immobilizer unit by attaching new keys to it. In the worst case, you will have to change both the ECU and the immo block. The procedure for connecting and disconnecting the immobilizer depends on the car.
For a number of models, there are firmwares with deactivated protection. They can remove the immobilizer lock permanently. After flashing the ECU, the engine starts without interrogating the protective unit. But since it becomes much easier to start a car with an unchip key, it is advisable to use firmware without protection only if there is a good alarm system.
How to understand that the battery in a car key is dead
If the battery fails, the key will not be able to start the car, and sometimes even provide entry into it. There is only one way out - change the battery. As a rule, the fact that “hour X” is about to come is indicated by the corresponding icon flashing on the panel. Appeared? It's time to disassemble the key.
Opening a car with a dead key is not an easy task: modern models do not even have the ability to do this mechanically. The problem will be solved by the so-called emergency element, which allows you to open the car and start it.
The emergency system of each brand is organized in a special way and the description of each is a subject for a separate discussion.
How can you tell if the battery is low?
- The range of a key operating remotely has been reduced, and significantly.
- A corresponding notification appears on the instrument panel.
- Car doors don't want to open.
- The vehicle cannot be started.
Which battery to buy
The golden rule for a motorist is not to buy a cheap “pill” for the key. This will cause the replacement to be made much more often, and problems may even arise in the system.
It is better to choose a battery similar to the one that was already installed in the key or opt for a well-known high-quality analogue.
In most cases, the car key is equipped with one of seven types of batteries. Some models have batteries that are recharged automatically - when the key is in the lock and the car is moving. But more often the battery is still a classic three-volt “pill”.
You can find out which one:
- After studying the operating instructions;
- By asking a question to an official dealer;
- Looking at thematic forums;
- Having disassembled the key body.
Frequently asked questions when the immobilizer does not work
In conclusion, we offer answers to the most common questions that arise if the immobilizer does not allow you to start, does not see the key, sees it only once, or all the keys with the chip are lost/broken.
Can the immobilizer work if the key battery is low?
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 engine start.
Do I need to use an alarm if I have an immobilizer?
Immo is not a full-fledged replacement for an alarm system, since it only complicates the thief’s task and does not prevent his access to the interior. The immobilizer does not allow it to start, but does not notify the owner in any way about a break-in attempt. Therefore, it is better to use both protective systems.
How to bypass the immobilizer when installing an alarm system?
There are two ways to bypass the immobilizer when installing an alarm system with an autostart system. The first is to use 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 system with auto start?
There are two options: the first - the crawler cannot scan the key normally (the chip has moved, the antenna has moved out, etc.), the second - the unit sees two keys at the same time: in the crawler and in the lock.
From time to time the car does not recognize the immobilizer key, what should I do?
If the immobilizer error occurs irregularly, you need to check the electrical circuits, contacts of the ECU and immobilizer unit, and the inductive coil transmitting signals to the chip.
Is it possible to link a new immobilizer to the ECU?
Sometimes the only way to start a car if the immobilizer is broken is to register a new unit in the ECU. This operation is feasible, as is binding a new controller to an old immobilizer unit, but the details 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 level. If it is normal, you should look for problems in the wiring. To prevent the keys from being disconnected and the immobilizer being blocked, 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 a linked key and password, unlocking is only possible with the replacement of the immobilizer and flashing the ECU with binding of a new immo block.
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.
We act quickly
Many car enthusiasts are inclined to simply go to a workshop and replace the battery there, but you can complete this simple task yourself. True, you will have to act like a sapper - that is, carefully and quickly, and therefore it is better to read the instructions in advance, having built a procedure in your head.
If the chip key does not have power, the code in the anti-theft device begins to gradually erase - that is, the immobilizer will not be able to do so for more than five minutes without a battery, otherwise the key will have to be synchronized with the central locking control key fob.
Special button
Each control panel has a special “Valet” button. Almost every car alarm manufacturer adds this button to the remote control just for emergency situations. If the purchase of a car took place in the showroom, then the manager had to show where this key was located.
In cases where the car was purchased on the secondary market, you should find out the answer to this question from the previous owner of the car.
Key disassembly procedure
Car keys can have different bodies. To disassemble such a product, you should:
- Study the instruction manual - there is a diagram according to which the key is disassembled;
- As a rule, the case consists of two halves, which can be separated by prying the latch with a thin object (knife blade);
- Sometimes a small screw is used as a fastener - in this case you will need a screwdriver;
The battery is sometimes located under a special cover. And this makes the task much easier - you don’t need to disassemble the key fob - you just need to move it, pressing lightly.
Once you have access to the battery, remove the old battery using tweezers and place a new one in its place. Then the car key body is assembled in the reverse order.
Restoring an old battery
Sometimes some are faced with a situation where the battery is obviously dead, and it is not possible to purchase a new one right away. The only way out is to try to “resurrect” the battery, which has obviously become obsolete and is located in the key fob.
First you need to remove it from there and then begin to act.
- The simplest way to “cheer up” the battery for a while is heating. But the main thing here is not to overdo it - extreme temperatures threaten an explosion.
- In some cases, the “old-fashioned” method also helps - you need to knock on the battery, intensifying the chemical reactions occurring inside.
- You can try to recharge the battery from other power sources - you will need a couple of wires and at least minimal skills. We should not forget: during such blasphemous manipulations the battery will heat up.
But these actions are only suitable in a situation like “alone in the taiga, a hundred kilometers from the nearest store.” Ideally, every motorist needs to have a spare battery with him - you never know.
The service life of batteries, even when not in use, is limited, and therefore it is periodically necessary to examine the “reserve” to see if the date of possible use has expired.
Having studied all of the above, it becomes clear: there is nothing complicated in replacing the battery of a car key, which is so scary for many - the main thing is to understand the scheme for disassembling the case and remember that the time of action is limited.
Video
The “Best China” channel presented a brief overview of CR2025 batteries purchased in China.
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