DETROIT, AP – The US government is investigating complaints of engine compartment fires in nearly 1.9 million Toyota RAV4 small SUVs.

The National Highway Traffic Safety Administration began investigating after getting 11 fire complaints involving the 2013 through 2018 model years.

The RAV4 is the top-selling vehicle in the US that isn’t a pick-up truck.

In documents posted on Monday, the agency said fires start on the left side of the engine compartment.

A terminal on the 12-volt battery may short to the frame, causing loss of electrical power, engine stalling or a fire.

Most of the fires happened while the vehicles are being driven but four owners complained that fire broke out with the engine off.

The agency said improper battery installation or front-end collision repair was a factor.

NHTSA said the RAV4 has a higher number of fire complaints in the battery area than comparable vehicles.

Investigators will try to understand better what is contributing to the fires.

The vehicles aren’t being recalled but the investigation could lead to one.