本试验程序概述了在制动噪声测功机上测试低频制动噪声（200 Hz至1.25 kHz）所需的必要试验设备（试验夹具、测功机、数据采集系统等）和试验顺序。它旨在补充SAE J2521，其重点是高频制动尖叫声。本RP适用于额定车辆总重低于4536 kg的乘用车和轻型卡车。在将此RP用于重型车辆之前，请咨询并同意测试请求者和测试机构。

This test procedure outlines the necessary test equipment (test fixture, dynamometer, data acquisition system, etc.) and test sequence required to test for low-frequency brake noise (200 Hz to 1.25 kHz) on a brake noise dynamometer. It is intended to complement SAE J2521, which focuses on high-frequency brake squeal. This RP applies to passenger cars and light trucks with a gross vehicle weight rating below 4536 kg. Before using this RP for heavier vehicles, consult and agree with the test requestor and the testing facility.