A wildcat strike at the CAMI Ingersoll location broke out Saturday afternoon.
Multiple reports to CTV London say a dispute between management and Unifor 88 Plant Chair Mike Van Boekel lead to the incident shortly after 3 p.m.
The situation was resolved and workers returned to their jobs around 7:30 p.m.
Workers will not be disciplined for the walkout.
General Motors is expected to release a statement sometime on Sunday.