U014D: Lost Communication with Mirror Control Module B

What it means

ECU lost CAN communication with mirror control module B. A communication loss with this module breaks any function relying on its data — diagnostic tools may show 'no response' and dependent modules can fall into limp mode.

At a glance

• Usually lights the warning light of the system that lost communication

How it works

Mirror Control Module B operates the vehicle's designated second mirror-control module and exchanges commands and status over CAN. U014D sets when the reporting controller no longer receives the expected messages from that module, so mirror functions assigned to it may stop responding.

Common causes

Most likely first.

1. Module unpowered
2. Gateway module routing CAN messages incorrectly
3. CAN terminating resistor (120 Ω) drifted out of spec

Symptoms

• Multiple warning lights may illuminate
• Affected modules may go into limp mode or shut down
• Specific functions inoperative depending on module
• Diagnostic tools may show communication faults

How to diagnose it

1. Scan all modules and note freeze-frame and related network codes to confirm that the missing response is specifically from Mirror Control Module B.
2. Check whether the mirror functions assigned to module B fail while other mirrors operate, which helps narrow the fault to this module or its branch.
3. Inspect the module's accessible connector and harness for looseness, corrosion, water, or damage, and check the relevant fuse.
4. Use a wiring diagram to verify module B's power and ground under the specified conditions.
5. Test the CAN wiring to module B for opens, shorts, or poor connections using the manufacturer's procedure.
6. If its power, ground, and network are sound, check gateway routing and confirm module response with a compatible scan tool.

Common fixes

• Replace a blown fuse or repair a poor power or ground connection to module B.
• Reconnect or repair a loose, corroded, or damaged module connector.
• Repair an open, short, or damaged CAN wire on the module B branch.
• Correct gateway routing or configuration if testing identifies it as the cause.
• Replace or configure Mirror Control Module B only after circuit checks pass.

Can I keep driving?

If the vehicle otherwise operates normally, you can generally drive cautiously, but check and adjust the affected mirror before setting off and do not rely on its power adjustment or related functions. Get the fault diagnosed if visibility is compromised or other electrical warnings appear.