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Car Limp Mode (Failsafe Mode Explained)

Updated: Jan 9

Car limp mode (also known as failsafe mode or limp home mode) is a safety feature built into most modern vehicles.


When a car enters limp mode, it means that its computer has detected a fault in one of its critical systems. In response to this fault, the vehicle will go into limp mode to protect itself and the engine from further damage.

 

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warning lights on a car dashboard

Symptoms of Failsafe Mode

When a car goes into limp mode, the driver may notice several symptoms, including the following.


  • Reduced power: The car may not reach high speeds and can struggle to maintain momentum on hills or when accelerating.

  • Loss of acceleration: The car may take longer to accelerate and may not be able to reach its usual top speed.

  • Warning lights: The car's dashboard may display warning lights, such as the check engine light or a warning light for the transmission or engine.

  • Reduced performance: The car's handling and braking may be affected, making it difficult to control the vehicle.

  • Auxiliary functions may stop working: Some functions not required for the car to run can stop working. This may include heating, air conditioning, blower fans, etc.

  • Limited RPM: The maximum rpm may be limited to, this could be 3,000 rpm, for example.

  • Limited top speed: Some vehicles, when in failsafe mode, may have their top speed limited; this could be 50 mph, for example.

  • Unusual noises: The car may make unusual noises, such as knocking or whining, indicating a problem with the engine or transmission. Though hearing unusual sounds isn't caused by the vehicle's failsafe mode, it's often associated with it.

  • Limp mode may lock automatic vehicles into low gear.


Additionally, the car may have reduced performance in other areas, such as handling or braking.


Common Causes of Limp Mode

There are many reasons why a car might go into limp mode. Some common causes include the following.


  • Faulty sensors: Many of a car's systems are controlled by sensors, which provide the car's computer with information about the car's speed, engine temperature, and other factors. If one of these sensors fails or provides incorrect information, the car's computer may go into limp mode as a precaution.

  • Faulty components: In some cases, a fault in a car's components, such as the engine or transmission, can cause the vehicle to go into limp mode. This is often due to a problem with the car's electrical system or a mechanical failure.

  • Overheating: If a car's engine overheats, the car's computer may go into limp mode to prevent further damage to the engine. This is a common problem in vehicles driven hard or not adequately maintained.


There are many other potential causes of limp mode, such as low oil pressure, a faulty throttle position sensor, or a problem with the car's fuel system. In most cases, limp mode is triggered as a safety precaution to protect the car and its engine from further damage.


If your car goes into limp mode, the best thing to do is stop driving as soon as it's safe and avoid starting the engine or driving until the issue is resolved. Continuing to drive the car while in limp mode can cause further damage to the car's engine and other systems.


What to Do if Your Vehicle Goes Into Limp Mode

If your car goes into limp mode, the best thing to do is stop driving as soon as it safe to do so and have it checked by a mechanic as soon as possible. Continuing to drive the car while in limp mode can cause further damage to the car's engine and other systems.


When you take the car to the mechanic, tell them that the vehicle is in limp mode. This will help the mechanic to diagnose the problem more quickly and accurately.


The mechanic will likely start by checking for any fault codes that have been generated by the car's computer, which can provide information about what caused the vehicle to go into limp mode


Once the mechanic has identified the cause of the problem, they will be able to repair the car and get it back to regular operation.


In some cases, the repair may be simple and inexpensive, such as replacing a faulty sensor or fixing a loose connection. In other cases, the repair may be more complex and costly, such as replacing a damaged engine or transmission.


It is essential to have the car repaired as soon as possible to avoid further damage and to ensure that the vehicle is safe to drive.


If you have a warranty on your car, they may cover the repair cost, so check with the manufacturer or dealership before paying for the repair out of pocket.

Should I Drive if My Car Is in Limp Mode?

It is not recommended to drive a car that is in limp mode. When a car goes into limp mode, it means that its computer has detected a fault in one of its critical systems. In response to this fault, the vehicle will go into limp mode to protect itself and the engine from further damage.


While the car is in limp mode, it will have reduced power and performance in other areas, such as handling or braking. This can make the vehicle difficult to control and put the driver and passengers at risk.


Additionally, continuing to drive the car while in limp mode can cause further damage to its engine and other systems.


Therefore, it is best to stop driving the car as soon as possible if it goes into limp mode. You should turn off the engine and tow the vehicle to a mechanic for repair.


Avoid driving the car or starting the engine, even if it seems to be functioning normally. This will only put the car and its occupants at risk and may cause further damage.


How to Reset / Turn Off Limp Mode

You may be able to reset the vehicle by turning it off and back on after around 30 seconds. If the warning lights go out and the vehicle operates properly, there might have been a temporary error.


However, pre-system checks may result in limp mode activating as soon as the vehicle is switched back on, or the problem may return after some driving.


If the vehicle returns to failsafe mode after resetting it, there may be a real problem, and you should investigate the issue.