ARCHIV: Das Logo von General Motors und ein blaues Lichtband zieren das Renaissance Center in Detroit (Foto vom 08.06.11).

General Motors' problems with its recall of roughly 1.6-million vehicles continue to mount. Now that it has emerged that GM knew about the problem since at least 2004 but waited to recall vehicles until February 2014, regulators at the National Highway Traffic Safety Administration have begun a much deeper investigation. NHTSA has sent a 27-page survey to GM that includes 107 questions about the timeline of what led up to the recall, and it has until April 3 to reply.

This isn't a simple, multiple-choice test. Automotive News believes that hundreds of pages could be required to answer some of the queries. NHTSA says that it is still investigating GM's response to the recall. "We are a data-driven organization, and we will take whatever action is appropriate based on where our findings lead us," said NHTSA in a statement on its website. If found liable, the automaker could face a fine as high as $35 million and even possible criminal charges, according to Bloomberg.

NHTSA's questions include a detailed explanation of GM's examination process; how it will improve the process; why a planned redesign of the cars' key in 2005 wasn't implemented; and specific data on each complaint it received. According to Bloomberg, NHTSA also has records that show the company had a meeting with regulators to discuss the airbag failure in a Chevrolet Cobalt in 2007.

New GM CEO Mary Barra has also hired an outside law firm to conduct an independent investigation about what happened. It will include questioning company employees who were involved with the process from the start. The recall stems from faulty ignition switches that shut off the car while driving, and if it occurs the airbags deactivate. Thirteen deaths and 23 crashes have been caused by the problem, according to Bloomberg. If you would like to peruse NHTSA's entire questionnaire for GM, it can be viewed here.