More recall trouble may be brewing for Toyota in the US where the National Highway Traffic Safety Administration (NHTSA) is eyeing Scion tC sunroofs.

The safety agency opened an investigation following nine reports of shattered glass panels - seven involving the retractable glass panel section and two the stationary glass section.

Some reports allege that breakage occurred while vehicles were being driven and one complainant reported cuts from the broken glass - all apparently ended up with an interior full of glass fragments.

If the investigation turns up a safety-related defect, NHTSA could could order a full recall.