A manufacturing deficiency may have damaged some tanks, potentially allowing fuel to leak.
Mazda has initiated two related recall campaigns for the 2014-2016 Mazda3, addressing a manufacturing defect that affects fuel tanks.
The company in April received the first field report of a weld failure on the tank, sparking an inquiry to determine the cause. After monitoring the tank supplier's production process, investigators determined that "inadequate facility control" allowed some tanks to become deformed during production.
"In this condition, welding of the recirculation pipe to the fuel tank may be insufficient and lead to a potential fuel leak," NHTSA filings explain.
Approximately 17,500 vehicles from the 2014-2016 model years will be inspected to determine if the tank is defective or the inlet check valve (ICV) weld has been damaged. If so, the fuel tank will be replaced as needed.
Service technicians will focus instead on the recirculation pipe in a smaller batch of around 3,850 vehicles from the later in the 2016-model-year production run, again replacing the entire tank if the systems do not pass inspection.