What’s In A Steering Column: Energy Absorbing Column

As vehicles are becoming more advanced, we are finding technology where it never was before. Sometimes it is in plain sight, such as infotainment systems, GPS, and a head-up display. However, sometimes it is concealed in places one may not expect.

Steering columns have gone from a basic shaft used to transfer movement from the steering wheel to the front wheels, to a highly complex part of the vehicle. Today’s steering columns have steering angle sensors, airbags, clock springs, heated steering wheels, and controls for multiple systems. Let’s take a look at collapsible steering columns.

Collapsible steering columns have been mandatory in the United States since the late 1960’s. These columns were designed to give way and shorten in the event of a collision. This was accomplished by mechanical means, such as a tube in a tube design. The intent was to absorb the collision forces and prevent the steering shaft and steering wheel from being forced toward the driver.

Many modern steering columns still have the same ability to collapse and absorb energy. However, they now have the ability to collapse from the force of the driver impacting the steering wheel airbag. There are multiple ways how this safety feature is activated.

In the event that the driver impacts the steering wheel in a collision, the steering column is designed to shorten. Some designs use a mechanical “pin” that will shear off with a specific amount of force, or a piece of metal that will deform in a controlled manner. Other vehicles have columns which use a pyrotechnic device to release a mechanism, allowing the steering column to lessen in length and absorb energy from the impact.

Post collision steering column inspection or measurement is recommended by many vehicle makers. While other OEMs require replacement of the column after the energy absorbing mechanism has been utilized. OEM service manuals will often provide this inspection and replacement information.

Due to the complexity of the system, the functions may be computer controlled. This also means that diagnostic trouble codes (DTCs) may be set if there are any malfunctions. A scan tool may be required to pull these trouble codes and diagnose any issues.

It is important to know if a vehicle is equipped with these features, what parts are used in the system, and where they are located. This will enable you to check for proper operation to ensure a complete, safe, and quality repair.

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