When your vehicle’s electronics systems detect severe engine or transmission issues that can compromise your safety, the systems on most vehicles built over the past 30 years will go into limp mode. This shuts down various non-essential systems and significantly slows down your car. While in limp mode, you should still be able to get to your destination safely; that’s what modern limp-in mode is for, but it can sometimes be challenging.
If, for example, there’s an issue with the throttle body control, you may not be able to accelerate above idle or you may not be able to achieve more than a very limited amount of throttle. This will typically be accompanied by a warning light on the dash that looks like a wrench or a cutaway throttle body.
If the transmission solenoids lose power, you may find that you only have second or third gear or you may feel the transmission shift very harshly due to increased line pressure, depending on the vehicle. There are other scenarios too numerous to list.
Here are some tips on how to safely limp your broken vehicle home if you find yourself in a situation where limp in mode renders your vehicle unsafe to drive:
In most cases, the limp mode on a car will automatically turn off your vehicle’s non-essential electrical systems, such as the air conditioning (A/C). This helps lighten the load on the engine, allowing it to cool down.
If your vehicle doesn’t automatically shut your electrical systems down, try turning them off yourself. Turning off your stereo, interior fan, and other non-essential electrical systems can give your vehicle the extra power boost it needs to limp home safely.
When your car goes into limp mode, you’ll likely notice a sudden loss of power or a difference in the way the transmission shifts feel. Some limp mode systems limit engine rpm. Depending on the reason for limp mode, the system may prevent you from accelerating or the vehicle may take off in a higher gear than first so you can drive fast enough to get to a safe place. For your own safety, it’s best to take the first available exit if you’re driving on the highway if the vehicle isn’t safe in traffic.
Some systems are programmed to protect the vehicle and will almost shut down completely; others will literally destroy themselves to keep you moving rather than putting you down beside the road. It’s all about the programmers’ priorities: protect the vehicle or protect the driver and passengers. One way or another, find a safe place if you can, particularly if you’re far from home.
A low or flat battery can trip your check engine light and cause your car to go into limp mode. In this case, a battery booster pack can restart your engine as well as act as a secondary power source as you drive. It can give your vehicle an extra push that might just be enough to help you get home.
If you’re lucky, there might be a garage or repair shop just around the corner. A mechanic can diagnose your car and help you resolve the issue faster. Limping your vehicle directly to a repair shop also saves you the trouble of towing your car there later on.
Sometimes, limp mode can be triggered by issues you can diagnose and resolve by yourself. Here are some ways on how to get your car out of limp mode:
No car is perfect, and temporary glitches can happen. If this is what triggered limp mode, then a quick restart should do the trick. Switch your vehicle off, wait for at least 60 seconds, and switch it back on again. This can’t hurt and is sort of like rebooting your PC. If limp mode was triggered by a small glitch, then your car should be back to normal.
When was the last time you topped off your transmission fluid or changed your engine oil? Limp mode can also be triggered when problems come about because of contaminated or insufficient transmission fluid, engine oil, or coolant. You may have to flush or refill these essential fluids to disable limp mode.
A dirty air filter can also cause your vehicle to go into limp mode, but only if it’s almost completely clogged. Note, however, that this isn’t a computer-triggered limp mode. It’s a genuine limp mode because the engine can’t breathe.
You’ll need to start by checking fluid levels (caution – don’t open a hot cooling system) and a visual inspection to see if there’s anything obvious that you can safely repair or bypass to get going.
If you have a scan tool, you can use it to retrieve any diagnostic trouble codes (DTC) that might have triggered the limp mode on your car. You can also use an ELM327 dongle and a phone app, which is inexpensive and might help figure out what’s wrong.
You can also use an ELM327 dongle and a phone app to scan for any DTC that might have triggered the limp mode on your car.
–Richard McCuistian, ASE Certified Master Automobile Technician
Permanently disabling limp mode is a bad idea. It might seem like a hassle to have to limp your faulty vehicle home, but it’s better than unknowingly driving your car until the engine, transmission, or other systems fail. It’s best to just fix whatever’s triggering limp mode instead of permanently disabling it.
They say prevention is better than cure, and that applies to your vehicle too. It’s much better to make the extra effort to prevent limp mode rather than fix it. Keep up with your manufacturer’s recommended maintenance and tune-up schedules. This will make sure your vehicle’s parts are all working as they should.
Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.