Following a production halt to its Japanese-market Outlander plug-in hybrids, Mitsubishi says it has detected the problem that led to several short-circuits, and a fire.

The company said in a press release batteries made by GS Yuasa resulted from a screening process added to the battery manufacturer’s line in December 2012.

“It was found that during this screening process the shape of an internal part of the battery cell was altered and some microscopic contaminants were generated as a result of battery cells being exposed to excessive force,” said Mitsubishi.

The solution will be to remove the screening process, says Mitsubishi as it prepares also for a recall of less than 4,000 Outlanders and some i-MiEVs also affected.

This hybrid version of the Outlander had been selling much better than gas-only counterparts, and the car has had some bugs including a separate incident involving its front and rear drive motors, also now being addressed.

Mitsubishi has apologized to its customers for inconveniences, and appears diligent in its
efforts to get teething problems worked out before the Outlander plug-in is launched in the U.S. early in 2014.