Code
U0180
HYUNDAI
U — Network/User
Lost Communication With Automatic Lighting Control Module
Views:
UK: 11
EN: 16
RU: 12
AI status
Completed
Completed
100%
Causes
- Power or ground fault at the Automatic Lighting Control Module (ALCM)
- Damaged or disconnected wiring or connector to the ALCM
- Faulty ALCM (internal failure)
- CAN bus wiring fault, short, open or intermittent connection
- Missing or failed termination resistor on the CAN network
- Other module(s) pulling the CAN bus down or causing bus errors
Symptoms
- Exterior lighting functions (auto headlamps, DRL, adaptive lighting) may be inoperative or defaulted
- Warning lamp or message for lighting or communication on instrument cluster
- Other modules that use lighting status may show faults or incorrect behavior
- Stored or repeating U0180 DTC; other network U-codes may be present
- Intermittent loss of lighting control or erratic lighting behavior
What to check
- Retrieve freeze frame and related DTCs from all modules with a capable scan tool
- Check for blown fuses related to lighting and body modules
- Visually inspect ALCM connector and harness for damage, corrosion, water intrusion or loose pins
- Confirm key on, engine off — verify module presence using scan tool (module list)
- Measure ALCM supply voltage and ground integrity at connector
- Inspect CAN_H and CAN_L continuity between ALCM and gateway/BCM and check for physical damage
Signal parameters
- Presence of ALCM module on scan tool module list (addressable)
- CAN_H / CAN_L idle voltages ~2.5 V (both lines) and dominant levels ~CAN_H 3.5 V / CAN_L 1.5 V (typical)
- Bus differential voltage when active (scan tool oscilloscope)
- CAN bus data rate (commonly 250 kbps or 500 kbps) and message traffic for ALCM message ID(s)
- Supply voltage to ALCM (battery voltage nominal 12 V) and ground resistance (
- Module wake/sleep messages and network availability (timestamps)
Diagnostic algorithm
- Connect a full-function scan tool; read and record U0180 and any other network DTCs from all modules.
- Verify vehicle battery voltage is sufficient. Check fuses for lighting/BCM/ALCM circuits; replace if blown and verify cause.
- Confirm the ALCM appears in the scan tool module list. If it is not present, proceed to wiring and power checks.
- With connector disconnected, measure supply voltage and ground at the ALCM connector pins to confirm proper power and a good ground.
- Inspect the ALCM connector and wiring for corrosion, bent pins, water, or damage. Repair or replace as needed.
- Backprobe CAN_H and CAN_L at the ALCM connector. Verify idle voltages (~2.5 V both) and differential during bus traffic with a scope or oscilloscope-capable tool. Check for short to Vb or ground.
- Check continuity of CAN wiring between ALCM and gateway/BCM and verify termination resistors (~60 ohms). Repair any opens/shorts.
- If wiring and power are good and CAN traffic is present but the ALCM does not respond, consider reflashing module software per service info or replacing the ALCM. Verify calibration and software compatibility if module was recently replaced.
- After repairs, clear codes, perform function tests and a drive cycle to ensure no reoccurrence. Monitor for related codes that may indicate other issues.
- If intermittent communications continue, capture CAN traffic logs during the event and inspect other modules for bus errors or high error frames.
Likely causes
- Corroded or loose connector pins at the ALCM
- Blown fuse supplying ALCM power
- Broken or chafed CAN_H or CAN_L wiring near harness routing points
- Failed ALCM due to water ingress or physical damage
- Aftermarket device or recent repair disturbed CAN wiring or connectors
Fault status
Status
Lost Communication With Automatic Lighting Control Module — ALCM not responding on the vehicle network. Check power, ground, connectors, CAN wiring and termination; module may be missing or failed.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
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