U015F: Lost Communication With Automated Driving System Interface Module B

What it means

ECU lost CAN communication with ADS interface module B (interface between automated driving compute and vehicle subsystems).

At a glance

• Usually lights the warning light of the system that lost communication
• The engine or gearbox may go into limp mode

How it works

Automated Driving System Interface Module B carries communications between automated-driving computing and other vehicle systems, separately from interface module A. U015F sets when the reporting module does not receive the expected network messages from interface module B for the required time, potentially interrupting functions routed through that interface.

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 for U015F and related communication codes, and review freeze-frame data for low voltage or a wider network disruption.
2. Check battery condition and charging-system operation, as low voltage can interrupt interface module B's communication.
3. Inspect Automated Driving System Interface Module B's power, ground, fuses, network connectors, and wiring for damage or corrosion.
4. Use a scan tool to check whether interface module B responds and identify which automated-driving or vehicle-system functions are affected.
5. If power and ground are sound, test the CAN wiring and gateway path for opens, shorts, or routing faults.
6. If the network path is intact, investigate interface module B and network termination according to the manufacturer's diagnostic information.

Common fixes

• Restore battery charge or repair a charging-system fault.
• Repair a blown fuse or poor power or ground connection to interface module B.
• Repair damaged network wiring or connector terminals, or correct a verified gateway routing fault.
• Repair a confirmed termination problem to the manufacturer's specification.
• Repair or replace Automated Driving System Interface Module B if its supplies and network path are sound.

Can I keep driving?

Do not rely on automated-driving or related assistance features while this interface fault is present; drive manually and remain ready to control the vehicle. Stop safely if warnings indicate that vehicle control or another essential function is affected.