CAN network

U0234 — Lost Communication with Lane Departure Warning Module

Severity: medium Safe to drive

What U0234 means

A control unit stopped receiving messages from the lane departure warning module, usually the camera behind the windshield, over the CAN bus. Modules normally exchange data constantly, so missing messages set this code. The cause can be the module itself, its power or ground, or the bus wiring.

Symptoms

  • Lane departure or lane keep assist unavailable
  • Forward safety warnings (such as collision alerts) off
  • Warning lamps on the instrument cluster
  • Other camera-based features not working
  • Driver assist system error message

Possible causes

  1. Failed forward camera or lane module
  2. Power supply or ground fault at the module
  3. Open, shorted or chafed CAN bus wiring
  4. Corroded connectors or terminals
  5. Another faulty module loading the CAN bus
  6. Camera misaligned or uncalibrated after windshield work
  7. Heavily dirty windshield area or camera lens

How to diagnose

  1. Run a full-module scan to see which modules communicate and which don't
  2. Review stored codes in other modules and compare them with U0234
  3. Check fuses and the power supply to the camera module
  4. Check the module's ground connection
  5. Inspect the camera harness and connector for damage, moisture and corrosion
  6. Measure CAN bus resistance and voltages at the diagnostic connector
  7. Clean the windshield and lens and check camera position
  8. Disconnect suspect modules one at a time only with a documented procedure

Common fixes

  • Restore the module's power or ground
  • Repair CAN wiring and connectors
  • Replace the faulty module or camera and calibrate it
  • Calibrate the camera after windshield replacement
  • Update module software if the manufacturer provides it

Questions and answers

What does U0234 mean?

It means communication with the lane departure warning module was lost. Other control units are not receiving its data on the CAN bus.

Can I drive with code U0234?

Usually yes, but driver assist features may not work. Have it diagnosed soon.

Can a windshield replacement cause U0234?

Yes. The camera may be misaligned or uncalibrated, or its connector may have been damaged during the job. Check this first.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.