U0189 is a network communication diagnostic trouble code indicating that the vehicle's control modules can no longer communicate with Digital Disc Player/Changer Module 'C' on the data bus. This typically points to an infotainment or rear-seat entertainment component rather than an engine or emissions problem. The code is set when the expected messages from that specific disc changer module are missing.
The most common cause is an internal failure within the disc changer/player module itself, causing it to stop communicating on the network while other modules continue to function.
Open, shorted, pinched, or corroded power, ground, or data-bus circuits between the module and the rest of the vehicle can interrupt communication.
A fault on the CAN, LIN, or other serial data bus segment serving this module—such as incorrect termination, bus shorting, or interference—can isolate the module.
A blown fuse, faulty relay, corroded ground point, or poor ignition feed can prevent the module from powering up and communicating.
The head unit or gateway module that manages communication with the disc changer may be defective, though this is less common than a module or wiring fault.
A failed engine or powertrain control module is an extremely unlikely cause of U0189; it should only be considered after wiring, power, ground, bus integrity, and the disc changer module have been ruled out.
No. U0189 is a communication code for an infotainment or digital disc player/changer module. It does not indicate an engine, transmission, or emissions fault.
Almost never. The PCM/ECM is rarely the cause of an isolated infotainment communication code. Diagnose the disc changer module, its wiring, power, ground, and data bus first.
Yes. This code normally does not affect engine operation, braking, or safety. It may simply mean the CD/DVD changer or related entertainment feature is unavailable.
The letter suffix identifies a specific instance of the module on the vehicle network. Multiple disc changer modules may be designated A, B, C, etc., depending on the vehicle configuration.