Jaguar "Low Battery, Please Start Engine". Why Do I See This?

Many drivers understand the importance of having a healthy battery in the car, and Jaguar tries to help you maintain your battery with its battery monitoring system (BMS). This system inspects the level of charge in the battery and displays warnings to keep you up to date on the state of your battery. One message that you're likely to see in your Jaguar is "Low battery, please start engine". What exactly does this message mean, and why does it show up?

Low battery, please start engine message highlights

• Common reasons:alternator or battery problems
• How to fix:check the voltage in various conditions, charge the battery, replace the battery
• Possible consequences:when battery dies, you will get stranded
• Priority level:High
• Can you drive?Yes
• DIY repair:Possible
• Repair price range:$150-$300

What Can Cause this Error Message

This message occurs when the car is in accessory mode and the battery's charge has fallen below a certain threshold. At this point, the battery monitoring system will display a message to warn the driver that the battery is low.

Normally, starting the engine will cause this screen to disappear, and letting the engine run for 30 minutes should charge the engine enough to get rid of the warning for a while.

If the message doesn't disappear after running the engine for 30 minutes, or if it repeatedly comes back after a short while, then there is probably an underlying issue that needs to be resolved.

Here are some of the causes of a recurring low battery message.

1) Old or Worn Battery

If the battery in your car is old or worn, it may not be able to hold a charge for an extended period of time. Similarly, if the battery is damaged, it may not charge at all. This can cause the "low battery" warning message to appear on the dashboard. It could also be responsible for the message recurring within a short period of time.

If this message keeps appearing or returns shortly after starting the engine, it may be due to an issue with the battery. It is important to address this issue as a weak or damaged battery can lead to other problems with the car and may leave you stranded if it dies unexpectedly.

2) Parasitic Drain in the Car

A parasitic drain is a continuous flow of electricity in a vehicle even when it is turned off. In Jaguar vehicles, this can be caused by various systems and components that continue to draw power from the battery, such as the alarm system, electronic memory systems, and any accessories that are left on.

Excessive parasitic drain can lead to a dead battery and require a jump start or replacement. One of the most common causes of a parasitic drain in Jaguar vehicles is storing the key too close to the vehicle. The car has a sensor that is constantly looking for the key. If the key is within 5 meters of the vehicle, this sensor will remain on, draining the battery even while the car is off.

A parasitic drain will result in the battery running out of charge quickly, meaning that you will often have to deal with the low warning message on the dashboard.

3) Problems with the Alternator

The alternator generates electricity to power the vehicle's electrical systems and to charge the battery. It works by converting the energy of the engine into electricity. The alternator is essential for keeping the battery charged and maintaining a stable power supply while the vehicle is in operation.

When the alternator fails or develops a fault, the car will drain the battery to run the engine. Starting the car will fail to remove the low battery warning since the alternator can no longer charge the battery.

4) Short Trips

Starting a car requires a lot of electrical energy. This is provided by the battery. Once the car is running, the electrical energy the car requires is provided by the alternator. The alternator also charges the battery while the engine is running.

The alternator needs to run for about 20 minutes to make up for the energy used to start the car. Driving the often for less than 20 minutes at a time will prevent the battery from charging. This will cause the battery to drain quickly.

5) Diagnostic Port

A known issue in some Jaguars is that this message will repeatedly occur after running a diagnostic scan. The issue is easily resolved by rebooting the BMS control module.

How to Fix "Low Battery, Please Start Engine"

Having a well-charged battery is very important to maintaining your car. If the battery is too low, important systems in the car could malfunction. You might also find yourself stranded and waiting for a jump if the battery dies suddenly.

Much like the warning says, the simplest way to solve this problem is to start the engine and drive the car. Jaguar recommends that you drive for at least 30 minutes to ensure that the battery charges sufficiently.

This is also the first step in diagnosing whether there is a deeper problem with the car. If the message disappears and stays gone after a 30-minute drive, then everything is fine, and the battery was simply too low.

If the message doesn't disappear after driving for 30 minutes, then there is a problem preventing the battery from charging. This indicates that your car might have a damaged battery or a faulty alternator.

If the message disappears after driving, but comes back shortly, usually within two weeks, then you are either dealing with a power drain in the car, a battery that can no longer hold a charge or a problem with the Energy Management Module.

• Reboot the Battery monitoring system

The Battery monitoring system (BMS) is responsible for monitoring the battery condition and charge level and will send warning messages depending on the state of the battery. In some situations, the BMS will develop a problem that causes it to erroneously report a low battery. When this occurs, the system will need to be rebooted.

Rebooting the Battery monitoring system is as simple as disconnecting the battery for 15-30 seconds. After this, you can reconnect the battery and start the car again. If the message is still displayed, you should start the engine and drive the car for about 30 minutes.

• Inspect the Battery

If this error message keeps coming up after driving for about 30 minutes and rebooting the Battery Management System hasn't caused it to disappear, then there may be a problem with the battery. It is possible that your battery is too old, or it is faulty and no longer holds a charge. If this is the case, you will need to replace the battery with a new one.

• Remove Any Plugged Devices

A common cause of parasitic drain is leaving devices plugged into the car when it is off. Some devices that remain on will not allow the car to shut down fully.

Remove any devices that are plugged into the car like chargers, displays, and dash cams after turning off the vehicle.

• Take the Car to an Automotive Electrician

If you suspect that the car is suffering from a power drain, you might need to have the car examined by an automotive electrician. This is because there are many electrical systems in a Jaguar, and it is difficult to identify which ones are draining the battery without proper equipment and knowledge.

• Replace the Alternator

If you have a faulty alternator, it will need to be replaced.

Replacing the alternator is a straightforward procedure, but the location differs depending on the model of your Jaguar. You might also need to remove some other parts of the engine to access the alternator.

If you are not comfortable working on engines, you can have a mechanic remove and replace the alternator for you. If you choose to replace the alternator yourself, make sure to get an adequate replacement part and consult the owner's manual or a repair guide for instructions on how to remove the alternator.

Conclusion

If you see the message "Low battery, please start engine" in your Jaguar, it means that the battery's charge has fallen below a certain threshold. Starting the engine should charge the battery enough to get rid of the warning for a while, but if the message persists or keeps coming back, there may be an underlying issue with the car's electrical system or computer.

This underlying issue could be an old or damaged battery, parasitic drain, or problems with the alternator. It could also be caused by repeatedly only taking short trips in the car, or by using a diagnostic scanning tool.

To fix this problem, you can try replacing the battery and alternator, and fixing any parasitic drain issues. If the problem persists, it is recommended to take the car to a mechanic for further diagnosis.