Mitsubishi admits having manipulated fuel-economy-related data on some vehicles for 25 years

Japan's Mitsubishi Motors has been plunged into crisis over a fuel-efficiency cheating scandal. Its stock plummeted by about half and there are serious questions being asked about the automaker's future.

Here is what we know so far:

Last week, the maker of the Outlander sport utility vehicle admitted it cheated on tests so some of its cars would look more fuel efficient than they were.

The scandal deepened Tuesday as the firm revealed it has been using an improper testing method for 25 years - longer than first thought. Unnamed employees also manipulated testing data to give Mitsubishi an edge against its competitors.

So far, the falsified figures affect more than 600,000 mini-cars, sold only in Japan. That includes models produced for rival Nissan which discovered Mitsubishi's dishonesty.

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The scale of the misconduct may be much bigger, however, and involve cars sold overseas. That would seriously inflate the scope of the crisis engulfing Mitsubishi.

Not quite. The scandal involving the German giant relates to software installed in around 11 million diesel cars sold globally that helped it evade emissions standards - making the cars seem less polluting than they really were.

Mitsubishi, on the other hand, manipulated testing figures so its cars appeared to get more kilometres for each litre of fuel.

An expert outside panel is looking into who knew what and when. Japanese regulators are also conducting their own probe. But whatever they find, big penalties and lawsuits are almost certain.

And it's a huge embarrassment for the company, which was caught a decade ago covering up serious parts defects. Mitsubishi almost went out of business but it was saved by a series of bailouts.

Tough to say

Some experts think its longstanding connection to a web of Japan's biggest firms - the Mitsubishi group - will save it from going under, and the jobs of some of its 30,000 employees.

But it's uncertain if they will be so willing to help this time.

Mitsubishi is among the smallest of Japan's major automakers and has the least amount of cash, so its size won't work in its favour.

It sold about one million vehicles last year, way below Volkswagen or top-selling Toyota, which moved over 10 million units in 2015 and posted huge profits.