A large number of modern cars are necessarily equipped with central locking. This is not the most reliable security element for a vehicle, but in combination with an alarm it allows you to achieve a truly high level of protection. If the first central locks (CL) caused a lot of controversy and were considered not reliable enough, as the automotive industry and security systems developed, the situation changed for the better. But locks can still fail from time to time. And if their proper operation is disrupted, the car owner should definitely know why this could happen and what to do in a specific situation. There are several options for malfunctions, each of which requires a specific algorithm of action on the part of the car owner.
Recommendations for repairing the central locking of a car.
Central locking device
In a simplified form, the central locking system consists of the following main elements:
- control module;
- controllers or microswitches;
- actuators or actuators.
The central lock can work both contact and contactless. In the first case, a key is used to open and lock it, in the second - a key fob.
When the system is locked with a key, the following processes occur:
- by turning the closing element in the well, the microswitches are activated;
- from them the signal is sent to the door control unit, and from there to the central control module;
- the module receives and processes the signal, activating actuators;
- the locking elements are fixed.
If actions are carried out without a key, the signal, when the button is pressed, is sent to the antenna in the central control module, where it is processed and sent to peripheral systems, the actuators block the locking mechanisms.
In this way, you can control not only the door mechanisms, but also elements of the trunk, hood, and gas tank flap.
A distinctive feature of the system’s functioning is that it is not related to the operation of the car itself. That is, it works regardless of the ignition state and when it is opened, engine operation is not blocked.
IMPORTANT! Unlike an alarm system, the central locking serves more for the convenience of the user than for the safety of the machine.
How the system works
The central locking system includes the following main blocks and components:
- central electronic unit;
- driver's door electronic unit (can be combined with the central unit);
- electronic units for driver, passenger and rear doors (may be missing);
- push-button switches for driver, passenger and rear doors;
- limit switches for closing windows and doors;
- control units and window lift drives.
In most car models, the power window and central locking control units are connected into a single system. When closing the doors, the central locking system must poll the limit switches of all windows so as not to accidentally park the car and guard it with the windows open. Therefore, the failure to close the doors is often associated with a malfunction of the window regulator controls.
For a 2005 VW Passat, the electrical circuit for the central locking looks like this:
- Drive, buttons and limit switches of the passenger door (hereinafter referred to as Dv);
- Passenger engine control unit;
- Window lifter control unit and rear left drive;
- Rear left drive motor, switches;
- Driver's switch;
- Driver's driver's side switches;
- Driver's control unit, internal;
- Control unit for rear right door and window lifter;
- Multifunctional control unit.
- Blocker.
- Central locking drive rear right motor
- Window lifter switches and buttons.
- Fuses serving the central locking system.
This diagram does not show and label all the elements, but it is clear that the circuit is very complex, perhaps the most complex among the main electronic modules of a car.
At the same time, the central locking control circuit has the longest electrical wiring, which is distributed throughout the vehicle interior and has flexible corrugated hoses at the points of transition to the door space. Among other difficulties, car doors have maximum mobility relative to the interior; their interior space is susceptible to corrosion.
Despite the above difficulties, car models after the 2000 release have fairly reliable electronic central locking systems; their main malfunctions are often determined by mechanical breakdowns, faulty contacts, and wear on the door suspension.
Main types of central locking malfunctions
There are various types of violations in the functioning of the device, in which the central lock does not work at all or does not work well:
- The system is unstable. In this case, it continues to act, but sometimes jams. This can manifest itself in rare failures to execute a command, spontaneous blocking of locks after they are opened, or termination of the functioning of the lock of one of the doors.
- A partial failure occurs. In such cases, situations may arise when the system closes but does not open the doors or functions under mechanical influence, but does not work with a button.
- The lock does not respond to key fob commands. This problem occurs most often and can be associated either with a failure of the remote control or with problems in the operation of the control unit.
- The mechanism does not open with the key. In this case, most likely some element in the door lock system has failed. If possible, you can try to open another door with the key.
Similar problems in the operation of the device can arise for various reasons. Very often the system fails due to faults associated with electrical wiring, especially in the areas of corrugated hoses and door entrance connectors. In addition, failure of mechanism parts: relays, fuses, actuators, key fob can lead to negative consequences. A dead battery will also prevent you from opening the car.
What to do if problems are detected with the Peugeot central locking system?
Most problems require professional service. You can fix the lock yourself only in two cases:
- If there is a desynchronization between the lock and the remote control, as a result of which the device no longer “responds” to the remote control buttons. In this case, there is a chance that by repeating the binding procedure you can solve the problem.
- If the device does not show signs of life, you can try to replace the fuses of the central locking circuits; this is often enough.
The central lock does not open from the key fob: solution
If the central locking does not open from the key fob, you must first determine the cause of the malfunction, and then take action to eliminate it.
IMPORTANT! The central locking system is quite complex and repairing it on your own requires some experience and tools. If this is not the case, it is better to contact a specialized company.
If you still want to test yourself and repair it yourself, you should act depending on the nature of the breakdown.
Fuse
The simplest thing you can do is check the fuse that controls the locking mechanism. The fuse box is usually located under the hood. To determine where the required element is located in the module, you will have to use the instruction manual.
The fuse fails in the following cases:
- As a result of a short circuit. In this situation, you will have to look for the location of the fault, otherwise the new fuse will have the same effect as the previous one.
- Due to overload. This is caused by the consumption of a large amount of energy by any device.
Relay
Often the cause of a malfunction, when the mechanism does not work with the alarm key fob, is a broken relay. Therefore, the owner of the car needs to make sure that it is functioning.
For this purpose, you need to find the place where the element is placed. Its location varies depending on the type and brand of car. This may be a special compartment designed for fuses and relays, or a part on any part of the system's electrical circuit. This issue can be resolved with the help of the instruction manual, which provides accurate information.
After this, the element should be dismantled and its functionality checked in one of the following ways:
- Using a multimeter. To do this, you need to apply a voltage of 12 W to the product and measure the resistance between the power terminals. If the relay is not broken, under the influence of current the resistance will become close to zero.
- Check the condition of the board. This can be done by disassembling the device. If the internal board has traces of burnt contacts, then the relay has failed and needs to be replaced.
- Close the system without a part. If in this case everything functions normally, then it is necessary to replace the relay with a new one.
Wiring
The most vulnerable point of automotive wiring is the area between the car body and the door. The wires here are hidden in an insulating corrugation, inside which they can be damaged or interrupted while using the machine. When the sash is open, the circuit often continues to operate as it closes. As soon as the door closes, the contacts move away from each other and the system stops responding. To confirm this, you can take the following steps:
- You need to open the door and click the close button. To do this, you can use a screwdriver, which must be inserted into the latch of the mechanism from the end. If the wiring is functional, the lock should respond and attempt to close the door.
- After this, you need to deceive the system and confirm to the control unit that the sash was closed. To do this, press the limit switch located in the door opening.
- Then you need to press the button on the key fob, which should lead to the lock opening. Pull the door handle and slam it shut. If the mechanism does not work in this position, the cause of the breakdown is the wiring.
You can use a multimeter to determine the location of the damage. Having established where the circuit break occurred, you need to replace part of the wiring or connect the contact and wrap it with electrical tape.
Battery
A dead battery can cause problems with the central locking system. If it dies, you need to recharge the battery. If the battery fails and there is no response to the charger, it will have to be replaced.
Keychain
If the key fob breaks, the system can be closed using the contact method with a key. Then you need to find out the reason for the remote control failure. The simplest is to drain the battery. In this case, you just need to install a new one. However, a breakdown of the internal board can also lead to problems. Then you will have to purchase a new device or resolder the contacts.
Control block
To check the operation of this device, you need to use a tester or multimeter. It is necessary to make sure that there is voltage in the control circuit, then check the power circuit. To supply current, you need to open the driver's door mechanism with the key or press the button on the key fob.
Actuator
In order to check the operation of these devices, you will have to remove the car trim and dismantle the mechanisms. Then it is necessary to clean and dry them, since high humidity could lead to malfunctions.
It is almost impossible to perform all these actions without experience. Therefore, if you are not confident in your abilities, contact a professional master. This is the only way to accurately identify the breakdown and make repairs without damaging the internal structure of the system.
First meeting
It also happens that the central locking system does not work at a long distance. Therefore, it is better to press the button in the immediate vicinity of the car and make sure that all doors are locked. If the lock does not work, then you cannot leave the car unattended. Go straight to service.
The central locking kit usually includes a key fob that allows remote control. Most locks are designed to operate remotely within 10 meters of the vehicle. To increase your own comfort, it is better to immediately install central locking on the doors and luggage compartment.
The station wagon works with a key and allows you to combine work with any alarm system.
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2. Battery in the key fob. Again, the car is armed/disarmed , which means the signal arrives.
Doesn't the key fob only do one thing? try to close it with the key and open it with the key fob, but in any case, disassemble the driver's door, there is a control activator (5 contacts), check the circuit between it and the signaling unit (white and brown wires, it seems), you can save time and start from the signaling unit, maybe somewhere caught his feet
#5 Offline David.N
Four times flame hero
It doesn't open or close from the key fob. When I open/close with the key, the central locking is activated on all other doors. I didn’t catch anything for sure, I’ll remove the door panel.
Changed: Meaning, 02/27/2012 - 19:50
Modified by: David.N, 02/27/2012 - 19:48
I checked all the fuses, they are all intact. Maybe the button has become glitchy? Maybe some limit switch is not working, how can I check the limit switches alone?
Moderators: ARKus, Batman
