This toothed belt transmits drive from the engine crankshaft to the alternator pulley. It sits in the front engine accessory drive system, where it maintains synchronous rotation between the two pulleys. A worn or stretched belt causes the alternator to under-speed, reducing charging output and triggering a dashboard warning. The belt is a V-belt profile, which relies on wedge action in the pulley groove to transfer torque without slipping. On installation, ensure the belt is tensioned to the manufacturer's specification and that the pulley grooves are free of debris or wear.