good read
The Active Noise Cancellation system is operational under the following conditions:
The amplifier has passed all self-diagnostic checks
All doors are closed
Battery voltage is between 9.5 V and 16 V
The vehicle cabin temperature is less than 140°F (60°C)
Engine speed is between 550 and 3000 RPM
ANC system Diagnostic Tips:
Inspect for any aftermarket audio components. If the audio system has been altered this will cause increased exhaust drone.
inspect for anything inside the truck that may be blocking the speakersand/or microphones.
Inspect for any DTC’s example: B0560, B1277, B127C, B127D, door ajar issues/DTC’s, etc.
Disable the ANC system by removing the AMP fuse. If the exhaust drone noise improves there may be an issue with the ANC system. Some examples of system issues have been: faulty speaker or subwoofer,speaker or subwoofer improperly wired (-/+ wires backward), speaker orsubwoofer inoperative, etc.
The Audio System Diagnostic CD EL-50334-6 contains audio tracks that can be used to test the speakers.
B. Inspect the exhaust system components for the following:
Loose and/or missing fasteners
Heat Shields
Joints and/or couplings: Nuts, bolts, studs, clamps, straps
Bracket and/or insulator mounting
Inadequate clearance to body and/or chassis components
Inspect with the exhaust system both COLD and HOT; in NEUTRAL, FORWARD and REVERSE gears
Improper alignment
Disconnected and/or missing insulators
Cracked, dry-rotted, and/or oil-soaked insulators
Stretched, twisted, broken, torn, and/or collapsed insulators
Bent, twisted, cracked, and/or deformed brackets
Repair and/or replace exhaust system components as indicated by the inspection.
C. Incorrectly seated and/or aligned powertrain components and/or exhaust systemcomponents may create a transfer path into the passenger compartment. Perform the following procedure to re-bed the powertrain/exhaust:
Loosen, but do not remove, all powertrain mounts and exhaust system hangers Ensure that the exhaust flexible coupling, if equipped, moves freely. Start the engine. Settle the powertrain by shifting the transmission from DRIVE to REVERSE. Place the transmission into NEUTRAL Turn OFF the ignition Tighten all of the loosened fasteners with the powertrain in a relaxed position.
D. If after performing the above suggestions and the concern has not been resolved, as a test, swap the exhaust muffler and tail pipe assembly from a known good truck.
If this corrects the concern, order and replace the exhaust muffler and tail pipeassembly.
If the concern is still excessive after performing the above suggestions and the vehicle is equipped with a 5.3L engine, engineering is aware of the issue and working on improvements to the exhaust system