Limp mode: what causes it and how to fix it
If your car suffers from an engine malfunction it will likely enter ‘limp mode’. Our guide explains what this is and what you should do if it happens
If your car suddenly loses power and warning lights on your dashboard come on, it’s likely your car has entered ‘limp mode’. In the event this happens, it’s important to understand why it’s occurred, what you should do when it happens and how you can remedy the issue.
What is limp mode?
Limp mode, also known as ‘limp home mode’, is designed to protect the car by minimising damage when a fault is detected. An onboard control unit recognises when there’s a fault and activates limp mode as a security protocol, resulting in the engine only providing enough power to get the car to a safe location.
What causes limp mode?
Thanks to lots of clever sensors that are linked to your car’s mechanical and electrical components, a car’s ECU (electronic control unit) will detect when a problem has occurred and trigger the limp mode safety feature if necessary.
Likely causes for your car entering limp mode range from faulty engine sensors and wiring to low fluid levels, such as engine coolant and oil. More serious issues include gearbox and clutch malfunctions or brake problems.
How do you know if your car is in limp mode?
When limp mode is activated, the least important features in your car, such as air conditioning and the stereo, will switch off and the ‘check engine light’ will appear on your dashboard. The most notable change, however, will be a sudden reduction in the car’s speed and, usually, a limit to the number of gears available (usually up to third gear). This is to prevent further damage to the car and potentially prevent an accident that could happen as a result of the fault
How fast does a car go in limp mode?
Limp mode will likely reduce your maximum speed to anywhere between 35 and 45mph, and revs (RPM) will be limited to 2,000 or 3,000. This is to allow you to continue driving at a safe speed until you’re able to stop and seek help. As mentioned above, it’s likely you won’t be able to shift above third gear.
What do I do if my car goes into limp mode?
If you notice that your car has gone into limp mode, keep calm and focus on getting your car home or to a safe place. Where exactly you decide to stop will depend on distances, how the car is behaving and how far you feel comfortable to drive it.
How do I get my car out of limp mode?
When you’ve reached a safe place, you should turn off your engine and ignition. If you believe the issue was a temporary glitch, or simply want to check if it’s corrected itself, it’s recommended that you wait 10 to 20 seconds before switching your ignition back on and turning the engine over. If the warning lights have disappeared and the car appears to be performing as it should, then it’s likely that limp mode was the result of a faulty sensor.
It’s still important to have your car checked over by a mechanic to ensure nothing is amiss and to prevent the car from unnecessarily entering limp mode again. If, however, your vehicle doesn’t reset, especially if you’re on the road side, you should call for roadside assistance.
How much does it cost to fix limp mode?
The cost of repairing your car will vary depending on what’s causing it to enter limp mode. More often than not, your car will stop going into limp mode when a faulty part is replaced, electrical wiring or connections are replaced or fixed, or critical fluids are topped up. Keep in mind that if your car keeps entering limp mode and you keep ignoring it, you could potentially be doing further damage and thus adding to the final repair bill.
Read our engine management light guide to learn the top five causes of an amber engine warning light.