A remote control that no longer responds is often the result of a dead battery, interference from other devices or desynchronisation between the key and the vehicle. These are issues that you can usually solve yourself without an expensive garage visit. Read below how to quickly regain access to your car.
Replacing the battery in your key
The most common cause of a non-functioning remote control is a dead or weak battery. Many owners of a Renault Master report this issue after a few years of use. Fortunately, replacing the battery is simple and inexpensive.
Most Renault Master keys use a CR2016 or CR2032 3V battery. These batteries are available in almost every supermarket, chemist or petrol station. Make sure you choose the correct voltage: always 3V.
Open the key housing by carefully sliding the two halves apart. You usually open it with your fingernail or a small flat object. Insert the new battery with the positive terminal facing upwards. Check that the battery sits firmly on the contact points. Sometimes a loose connection causes malfunctions, even if the battery itself is still good.
‘ Never use WD40, as this actually damages the contacts. ’
Checking for loose contacts
In some Renault Master keys, the battery comes loose from the contact points due to vibration, shaking or dropping. You can solve this by opening the remote control and removing the battery. Then refit the battery and press it down lightly. Check that the contact points are clean and not corroded. If they are dirty, clean the contacts with a special electronic cleaner spray or contact cleaner. Never use WD40, as this actually damages the contacts.
Re-synchronising the remote control
If the battery is fine but the remote control still does not work, the key may have gone out of sync with the vehicle. This sometimes happens after a battery replacement or if the key has not been used for a while. Fortunately, you can restore this yourself with a simple procedure:
- Unlock the front door on the driver’s side manually with the emergency key
- Get in and insert the key into the ignition
- Switch on the ignition and start the engine
- This will automatically re-synchronise the remote control with the vehicle
This method works for most Renault Master models. After this procedure, test whether the remote control responds again by locking and unlocking the vehicle.
Interference from other devices
Devices that operate on the same frequency as your remote control can cause interference. Think of mobile phones, wireless equipment or other electronic systems nearby. This is often a temporary problem that disappears as soon as you move to a different location.
Areas with strong electromagnetic radiation, such as close to high-voltage pylons or transmission masts, can also affect how it works. In those cases, operate the vehicle manually with the emergency key until you are out of range of the interference.
‘ This is often cheaper than a completely new key. ’
Defective micro switches in the key
If replacing the battery and re-synchronising do not help, the micro switches in the remote control itself may be defective. These small switches fail due to normal wear or external damage. You can recognise this problem when the buttons no longer respond, even with a new battery.
Replacing a defective micro switch can be done without new programming, provided you keep the original circuit board and transponder. This is often cheaper than a completely new key. When you open the key, also check whether there is any water or moisture damage to the circuit board. If necessary, carefully clean the board before reassembling everything.
Vehicle-specific issues
Sometimes the problem is not with the key but with the vehicle itself. A few situations that can cause the remote control not to work:
- The engine is still running: while the engine is running, it is not possible to lock or unlock the vehicle with the remote control. Switch off the ignition first
- Defective UCH unit: in older Renault Master models from around 2003–2008, water damage and corrosion to the UCH/BSI control unit (the central control unit that controls, among other things, the central locking and remote control) are common
- Electrical faults: a weak battery or other electrical problems can affect the receiver in the vehicle
If the UCH unit is defective, you will have to have the unit replaced. This is specialist work and often also requires reprogramming of the key.
Use the emergency key
All Renault remote controls have a built-in emergency key. This is a physical key with which you can manually lock and unlock the doors. It is a reliable solution if the battery is empty or the remote control fails. The emergency key is usually located on the side or back of the remote control and can be slid out or folded out.
Always keep the emergency key with you and make sure you know how to use it. This prevents you from being left outside your vehicle at inconvenient times.
‘ Do not store the key together with other metal objects that could damage the contacts. ’
Preventive tips to avoid problems
Batteries in remote controls are cheap. Consider replacing the battery preventively if your remote is more than two to three years old, even if it still works. This prevents you from suddenly ending up without a working key.
Do you have two remote controls? Then test both regularly to determine whether any problems are specific to one key or to the vehicle itself. This helps you identify the cause more quickly.
Handle your remote control with care. Avoid drops, water and extreme temperatures. Do not store the key together with other metal objects that could damage the contacts.
When to see a specialist
If none of the above solutions work, there may be a deeper problem with the electronics of the vehicle or the key. In that case, it is sensible to contact a Renault dealer or specialist car mechanic. They can scan the key and the vehicle with diagnostic systems and determine exactly where the problem lies.
Sometimes the key needs to be reprogrammed or the UCH unit has to be replaced. These are tasks that require specialist knowledge and equipment.
On the Carnews website you can find further articles on common car problems, maintenance tips and practical guides for various makes and models.
Frequently asked questions
The most common causes are a dead or weak battery in the remote control and poor or loose battery contacts in the key itself. The remote can also lose synchronisation with the car, meaning it has to be reprogrammed. Defective micro switches, moisture damage or other damage to the circuit board are also common. In some cases, malfunctions due to external interference or a defective central electronic unit of the car play a role.
First check whether the battery is not empty: replace it with a new one, paying attention to the correct type and whether the positive and negative sides are in the right position. Carefully open the remote control and check whether the battery is firmly fixed and the contact points are clean and not corroded; if necessary, gently clean them and click everything back into place. Test whether a possible second key does work, to rule out that the problem is with the car rather than the key, and try to re-synchronise the remote by opening the door with the key and switching on the ignition. Finally, check whether the circuit board and buttons (micro switches) are visibly damaged or wet; in the case of clear damage, repair or replacement of the key is necessary.
Replace the battery preventively every few years and check that it is firmly in place and that the contact points are clean and dry. Do not drop the remote control and avoid exposure to moisture or extreme heat to prevent damage to the circuit board and micro switches. If necessary, gently clean the contacts with a suitable electronic cleaner (no WD40). Ideally, use two keys alternately so that wear and defects become apparent more quickly.
It is sensible to go to a specialist garage with a non-working remote control if a new battery, cleaning the contacts and re-synchronising with the car do not solve the problem, or if there is visible damage/moisture damage or suspected electronic faults (such as a defective UCH/BSI unit). If both keys do not work, this often points to a problem in the vehicle rather than in the key itself. A specialist garage charges on average about €40–€80 for a comprehensive diagnosis of the remote control and the related locking system. The costs for repair or replacement (for example micro switches or a new key housing) are usually between around €80 and €250, depending on the type of key and any programming required.
You can often re-synchronise the remote control yourself by opening the driver’s door with the key, switching on the ignition and briefly starting the engine. Then switch off the ignition again, get out and test whether the remote control responds. If this does not work, check whether the battery has been fitted correctly and the contact points are clean and firmly in place. If the remote still does not work, further programming is usually specialist work for a garage or key service.
