Alternator Front Bearing Failure

NHTSA's Office of Defects Investigation (ODI) opened a Preliminary Evaluation after reviewing field reports concerning alternator front bearing failures that cause elevated temperatures within the engine compartment, resulting in the fire suppression system (FSS) activating, immediately shutting the engine down, and rendering the bus inoperable.Analysis of the data provided by Prevost Car (US) Inc. showed high failure frequency and thermal events. An immediate shutdown of the bus can increase the risk of a crash or injury of bus occupants. In response to this investigation, Prevost Car (US) Inc. and Volvo Bus Corporation decided to conduct recalls 22V-221 and 22V-222. By submitting Part 573 Defect Information Reports on April 6, 2022, Prevost Car (US) Inc. and Volvo Bus Corporation notified ODI of a safety defect in certain model year (MY) 2010-2023 Prevost H3-45; X3-45; X3-45 Com; H3-45 VIP: X3-45 VIP and 2020 Volvo 9700 vehicles; some of these buses may have experienced thermal events after failure of the alternator front bearing, because the alternator belt continues to turn the alternator after the bearing failure.These recall actions address the safety concern that led to the opening of this investigation.Therefore, with these recall actions, this investigation is closed. The recalls encompass all model and MY vehicles addressed by the investigation. However, the closing of this investigation does not constitute a finding by NHTSA that a safety-related defect does not exist in other model or MY vehicles outside of the recall scope. The agency reserves the right to take further action if warranted by the circumstances.