DETROIT -- The National Highway Traffic Safety Administration on Monday upgraded a defect investigation in older Ford cars and SUVs over what it believes to be "unreasonable risk to motor vehicle safety."

Of concern is a risk that the timing belt may fail and cause the vehicles to lose power. The U.S. auto safety regulator opened the investigation into the issue in December, and it covers about 135,000 2014-17 Ford Fiesta, 2015-18 Focus and 2018-2021 EcoSport vehicles with 1-liter engines. The upgrade brings the probe to an engineering analysis for component and vehicle testing, which is a required step before NHTSA could seek to require Ford to issue a recall.

Ford spokesperson Mike Levine said the Dearborn automaker is notifying customers of a "revised maintenance interval" for the 1-liter EcoBoost timing belt, reducing the original 150,000 miles or 10 years to 100,000 miles or 6 years. The non-safety customer satisfaction program covers about 147,000 vehicles, including the 2014-2017 Fiesta, 2015-2021 EcoSport, and 2015-2018 Focus

"This customer satisfaction program will also offer reimbursement to eligible customers who previously paid to have their engine repaired or replaced due to a timing belt related issue," Levine said in a statement. "We are working with NHTSA as it continues to investigate."

All three models have been discontinued.

NHTSA has reports of 355 incidents that mostly feature a low engine oil pressure warning lamp preceding a complete loss or reduction of power while the vehicle is in motion.

In its original probe, NHTSA said it found timing belt material may degrade, resulting in debris clogging the mesh oil pump pickup-screen. That can create reduced engine oil pressure. The agency suggested drivers are experiencing the failure without sufficient warning and despite proper and routine oil changes.

NHTSA found the issue happening around 70,000 miles and that 98% of the failure happened prior to the 150,000-mile suggested timing belt replacement. Some complaints said customers paid thousands of dollars to fix the issue.

Ford has faced scrutiny in recent years for its quality and recalls. That prompted a transformation of its quality processes, which the automaker says is yielding results as shown in its top mass-market ranking in JD Power's Initial Quality Study. Still, Ford has issued more than double the recalls this year of any other automaker after breaking a record in 2025 for the number of recalls issued in a year. Ford also remains under an independent federal monitor to oversee its recall processes, data analytics and compliance.

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