Faulty pedestrian alert control module or its internal power supply; Damaged or corroded wiring harness between the module and the CAN bus; Blown fuse or poor ground connection for the pedestrian alert module; CAN bus wiring fault such as an open circuit or short to ground or power; Water intrusion or physical damage to the module connector; Low battery voltage or charging system issue causing network communication dropouts; Software or configuration mismatch after module replacement or battery service

DTC codes / U01xx · Lost communication with a control module / U013F

U013FLost Communication With Pedestrian Alert Control Module

Q: What does code U013F mean?

Lost Communication With Pedestrian Alert Control Module. U013F is a generic network communication code indicating that the engine control module or another primary module has lost contact with the pedestrian alert control module over the vehicle's controller area network (CAN) bus. The computer has detected that expected periodic messages from the pedestrian alert module are missing, which typically sets a communication fault rather than a direct component failure.

U013F is a generic network communication code indicating that the engine control module or another primary module has lost contact with the pedestrian alert control module over the vehicle's controller area network (CAN) bus. The computer has detected that expected periodic messages from the pedestrian alert module are missing, which typically sets a communication fault rather than a direct component failure.

SystemNetwork

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaLost communication with a control module

Symptoms you may notice

Audible pedestrian warning system may stop producing sound at low speeds
A warning light or message on the dashboard indicating a system fault
Often no symptoms besides the warning light, with the vehicle driving normally
Other driver assistance features may be disabled or show errors if they share the network
Intermittent operation of the pedestrian alert sound depending on temperature or vibration

Common causes, most likely first

Faulty pedestrian alert control module or its internal power supply
Damaged or corroded wiring harness between the module and the CAN bus
Blown fuse or poor ground connection for the pedestrian alert module
CAN bus wiring fault such as an open circuit or short to ground or power
Water intrusion or physical damage to the module connector
Low battery voltage or charging system issue causing network communication dropouts
Software or configuration mismatch after module replacement or battery service

How to diagnose and fix it

Verify battery voltage and charging system output to rule out low-voltage communication faults
Check all fuses and grounds related to the pedestrian alert control module
Inspect the module connector and wiring for corrosion, water intrusion, or physical damage
Use a scan tool to read live network data and confirm whether the module is completely offline or intermittent
Perform a voltage drop test on the CAN bus wiring and repair any open or short circuits
If wiring and power are good, substitute a known-good module or perform a module reflash per manufacturer procedure
Clear codes and road test to confirm communication is restored and no new codes set

What most technicians overlook on U013F

A weak or failing battery is a frequent hidden cause of U013F because the pedestrian alert module may drop offline during cranking or low-voltage events, setting a communication code without any module failure.
The code can be set by a completely different module on the same CAN bus that is shorting the network, so always check for other communication codes before condemning the pedestrian alert module.
After replacing or disconnecting the pedestrian alert module, some vehicles require a configuration or initialization procedure, and skipping it will immediately reset U013F.
Intermittent U013F that appears only in wet weather often traces to water ingress at a connector or a chafed harness in the front bumper area, not the module itself.
A scan tool that only reads generic OBD-II codes may not access the pedestrian alert module, so a factory-level or enhanced diagnostic tool is often needed to confirm the module is truly offline.

Can I keep driving with U013F?

The vehicle remains safe to drive in most cases because the pedestrian alert system is an audible warning aid, not a safety-critical control. Avoid relying on the pedestrian alert sound and have the fault diagnosed soon, especially if other communication codes or warning lights appear.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.