TOKYO -- Mitsubishi Motors' fraudulent fuel-economy testing went unnoticed until brought to light by partner Nissan Motor, showing efforts to improve compliance in the wake of previous scandals have had little effect.
The two Japanese automakers cooperate on the development and production of minicars. Nissan uncovered discrepancies between fuel-efficiency figures Mitsubishi reported to Japan's transport ministry and those arrived at under proper test conditions in fall 2015 while at work on next-generation models.
