Three weeks after the incident of a Proton X90 catching fire, Proton has completed its investigation into the affected vehicle. Poor grounding connection has been identified as the root cause, and no fault is found with the 48V mild-hybrid battery.

“As a safety measure, all Proton X90 owners will be contacted individually by Proton 3S/4S dealers to bring their vehicles for inspection and if required, remedial action will be taken by the service centre to eliminate any thermal risk,” said Proton in a Facebook post.

Although all X90 units on the road will need to be inspected, Proton says that this is not a recall exercise. 

“Additionally, Proton and its vendors have taken countermeasures by enhancing our supplier process control and incoming inspections on the Proton X90’s production line.

"Finally, Proton would like to confirm the mild hybrid (48V) battery used by the Proton X90 is not a source for the incident and would like to reassure everyone, the quality of our products and safety of our customers is the company's top priority," said Proton in its post.