NHTSA escalates Toyota Highlander investigation

The agency will now conduct an engineering analysis to determine why Highlander steering columns are failing.

The National Highway Traffic Safety Administration has stepped up its investigation into complaints of Toyota Highlander steering column separation.

The agency has identified 14 incidents involving complete steering column separation, including six failures while driving and one incident involving a minor crash. Another 16 incidents in which the column dropped from the dashboard mounting brackets but did not separate.

Focusing on the 2008-2013 Highlander, the inquiry appears to have narrowed its focus to the breakaway components that are designed to collapse or shear during certain types of vehicle collisions.

"There is no direct method for detecting when the capsules in the subject vehicles have sheared. If the driver operates the tilt/telescoping feature after the breakaway capsules have separated, the steering column may drop out of position and could subsequently detach entirely from the rest of the steering assembly," the NHTSA says. "Loss of steering while driving may cause a loss of vehicle control, which could lead to a vehicle crash."

Investigators have now launched an engineering analysis to determine what conditions can cause the steering column breakaway capsules to separate and what factors contribute to a failure to detect and repair the capsules after they have separated.

Toyota has revised its collision repair manual to partially address the concerns but has not yet issued a formal recall.