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Purpose:

Explain what Limp Mode means.

What is Limp Mode?

Limp Mode, also known as Limp-Home Mode or Fail-Safe Mode, is a safety feature employed in modern vehicles with electronic engine controls. When certain faults or malfunctions are detected in the engine or transmission systems, the vehicle's computer system can initiate Limp Mode as a protective measure.

Limp Mode icon on vehicle dashboard

The purpose of Limp Mode is to limit the vehicle's performance and prevent further damage to the engine or transmission. It allows the vehicle to be driven to a safe location or a service center with reduced power and speed. Limp mode is typically activated when the computer system detects a fault that could potentially lead to severe damage or unsafe operating conditions.

When a vehicle enters limp mode, it usually exhibits the following characteristics:

• Reduced Power: The engine power output is limited to prevent stressing the engine or transmission. The vehicle may have difficulty accelerating and reaching higher speeds.
• Limited Speed: Limp Mode may impose a maximum speed limit, usually around 40-50 mph (64-80 km/h). This prevents the driver from driving at high speeds that could exacerbate the underlying issue.
• Restricted Gear Range: In some cases, the transmission may be locked into a specific gear, such as 2nd or 3rd gear, to prevent shifting-related issues and maintain control over the vehicle.
• Warning Lights: Limp Mode is often accompanied by illuminated warning lights on the vehicle's dashboard, such as the check engine light or a transmission-related warning light. These lights indicate that a fault has been detected and the vehicle has entered Limp Mode.

Example

One scenario that would cause a transmission to go into Limp Mode is if the cable harness going to the transmission is damaged or disconnected. In this case, the computer will know that it lost communication with the transmission, but since the harness is detached, the command to go into Limp Mode cannot make it to the transmission. However, with no power supplied to the solenoids, the line pressure is set too high, and the transmission is stuck in 2nd or 3rd gear. This is the same effect the Limp Mode command would have.

What You Should Do

If your transmission is in Limp Mode, your transmission has a problem and you should get it fixed as soon as possible. Here is what you should do:

- Do not panic! Limp mode is specifically designed to limit further damage and allow you to get your car to a service center.

- If possible, drive directly to a service center.

- Otherwise, drive home and call a service center to have your vehicle towed.

- If you do not feel comfortable driving at a limited speed, pull off the road where it is safe to do so and call for a tow.

- It's advised that you do not continue to drive a vehicle in Limp Mode as it is unsafe and can cause further damage to your vehicle.

- We sell wireless dongles, scan tools, and tablets that will read and clear Limp Mode-related codes. Click HERE to get to our OBD2 scanners. These tools can be purchased from Amazon, Summit Racing, Advanced Auto, O'Reilly Auto Parts, and AutoZone as well.

It's important to note that Limp Mode is a temporary measure intended to protect the vehicle from further damage. Once the underlying issue is resolved, the vehicle should return to normal operation. To diagnose and fix the problem, it is recommended to consult a qualified mechanic or use a diagnostic tool to retrieve error codes from the vehicle's computer system.

It's worth mentioning that different vehicle manufacturers may have variations in how they implement Limp Mode and the specific symptoms experienced by the vehicle. Therefore, consulting the vehicle's owner's manual or seeking professional assistance is always advised when encountering Limp Mode.

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