Japanese truck and bus maker Mitsubishi Fuso, whose brand has been tarnished by a swathe of defect reports, is to recall 450,000 more vehicles.
Many more potential defects have been identified
The admission comes on top of 180,000 vehicles recalled last month.
Mitsubishi Fuso - owned 65% by German DaimlerChrysler and 20% by Mitsubishi Motors - may face further defect woes.
The firm has already identified 43 new problems; the transport ministry, meanwhile, said last week that there were 93 cases.
The recall further complicates the relationship between Fuso's German and Japanese parents.
Mitsubishi Motors won a $4bn bail-out agreement from a group of investors last month, after DaimlerChrysler said it would inject no more money.
Mitsubishi is the only major Japanese car maker to be consistently in the red and is seen as in need of emergency surgery.
The problems at Fuso have already led to the arrest of Katsuhiko Kawasoe, the former president of Mitsubishi Motors.
And DaimlerChrysler has said it may seek some form of compensation from Mitsubishi Motors for the problems at Fuso.