Navistar notified NHTSA this week that more than 4,000 of its IC Bus vehicles are being recalled to address high idle speeds.

The recall affects BE, CE and RE school bus models manufactured between 2006 and 2005 that are equipped with VT365 diesel engine calibrations of PAN2PVRO, PAN2PVR1 or PAN2PWR. Navistar explained that these engines should return to a low idle speed of 800 rpm and disable the driver's ability to increase engine speed in the event of a failed open accelerator position sensor circuit fault. If the open circuit corrects itself within 30 seconds of initiation, the low idle engine speed could suddenly increase to 1,200 rpm. This could cause an unexpected shift in vehicle position, possibly resulting in property damage, injury or death.

Customers and dealers were expected to be notified of the recall by mid-August. Navistar said it will repair the affected school buses free of charge.