U0187: Lost Communication with Disc Player Module

What it means

A control module is not receiving expected messages from Digital Disc Player/Changer Module A. Disc playback functions may be unavailable; the code alone does not identify why communication was lost.

How it works

Digital disc player or changer module A supplies disc playback and may report its status over the vehicle network. U0187 is set when the reporting module stops receiving the expected messages from that player for the specified time. An unpowered player, a broken CAN connection, or incorrect gateway routing can prevent communication without proving the player itself has failed.

Common causes

Most likely first.

1. Disc player unpowered
2. CAN wiring to disc player broken
3. Gateway module routing CAN messages incorrectly

Symptoms

• Disc playback functions may be unavailable
• Other communication codes

How to diagnose it

1. Scan all modules and review freeze-frame data and related communication codes to establish whether the loss is isolated to disc player module A.
2. Check whether the disc player powers up and whether disc playback or its status display is unavailable.
3. Inspect module A's connector and accessible wiring for looseness, corrosion, or damage, especially if the player was recently serviced or removed.
4. Verify the player's power and ground against the vehicle wiring diagram and manufacturer specifications.
5. Test the CAN connection at the player and assess gateway routing if power and ground are present.
6. If the circuits and network pass, evaluate disc player module A with vehicle-specific diagnostics.

Common fixes

• Restore the player's power supply or ground if testing identifies a fault.
• Secure or repair loose or corroded disc player module A connectors.
• Repair a damaged CAN wire to the player.
• Correct a confirmed gateway message-routing fault.
• Replace or configure disc player module A only after its supplies and network connection are verified.

Can I keep driving?

This fault generally affects disc playback rather than vehicle control, so driving is usually unaffected. Check for additional communication codes if other electrical or vehicle functions are also malfunctioning.