CADILLAC, CHEVROLET, GMC

PIT5404

2015-05-01 · NHTSA 10114512

車型關聯可作查閱線索；引擎、生產範圍與軟體條件請核對原廠資料。

原廠摘要

以下為英文原文

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

僅在原廠、通報編號、發布日期和完整摘要一致時，才合併重複登錄，並保留原始編號。舊資料仍可查閱；確認明確取代關係後才標示後續版本。1994 年以前的車輛關聯與預設結果分開顯示；未註明年式不等於所有年式適用。