CADILLAC, CHEVROLET, GMC

PIT5404

2015-05-01 · NHTSA 10114512

车型关联可作为查阅线索；具体发动机、生产范围和软件条件请核对厂商资料。

厂商摘要

以下为英文原文

This Preliminary Information communication provides information to the technician on the steps to diagnose and repair vehicles that may have a buffeting vibration and/or drone type noise, exhaust tone change, and/or body pressure booming. The concern may be most noticeable while the engine is operating in 4-cylinder Active Fuel Management mode in the 1,100-1,400 RPM range. If the noise is excessive it may excite the roof sheet metal and compound the issue, if this concern is found refer to the latest version of PIT5318. If the concern is qualified to be present during V4 mode operation, but is deemed to be normal by comparing to a like vehicle, then no further repairs should be made, as this is a normal characteristic. If the concern is qualified to be present during V4 mode operation, but is deemed excessive by comparing to a like vehicle then continue with the direction in the Preliminary Information. Vehicles equipped with the 6.2 liter engine and noise cancellation, the noise cancellation may not be working or working incorrectly this can be the cause of the issue. Technician should inspect for aftermarket audio components, objects blocking the microphones or speakers, Diagnostic Trouble Codes B0560, B1277, B127C, or B127D. By the technician pulling the fuse for the amplifier the noise cancellation will be disabled if the noise improves there may be an issue with the noise cancellation system. Technician should inspect the exhaust system also. Exhaust should be checked when it is hot and cold while the vehicle is in neutral, forward and reverse gear. Inspect the exhaust system for loose and/or missing fasteners, heat shields damaged, joints and/or couplings not properly seated, bracket and/or insulator mounting concerns, inadequate clearance to body and/or chassis components, improper alignment, disconnected and/or missing insulators, cracked, dry-rotted, and/or oil-soaked insulators, stretched, twisted, broken, torn, and/or collapsed insulators, and bent, twist

仅当厂商、通报编号、发布日期和完整摘要一致时，重复登记才会合并展示，原始编号仍予保留。旧资料继续供查阅；确认明确替代关系后才标示后续版本。1994 年以前的车辆关联与默认结果分开显示；未注明年款不等于适用于所有年款。