Code
U0180
Generic
U — Network/User
Lost Communication With Automatic Lighting Control Module
AI status
Completed
Completed
100%
Causes
- Blown fuse or loss of module power/ignition supply
- Poor or missing ground connection to the ALCM
- Damaged, corroded, or loose connector at the ALCM
- Broken, shorted or high-resistance CAN/wiring harness between ALCM and network
- Faulty CAN transceiver inside the ALCM
- Network short (short to battery or ground) or missing bus termination
Symptoms
- Automatic headlights, daytime running lights or adaptive lighting not functioning
- Warning message or icon related to lighting or network on dash
- Multiple network communications DTCs present or other modules reporting ALCM not responding
- Intermittent operation of lighting features or lights stuck on/off
- Scan tool cannot communicate with ALCM or module does not appear in network list
What to check
- Read all network DTCs and freeze frame data with a capable scan tool; note related U-codes
- Check battery voltage (key on) and condition; low voltage can cause comms faults
- Inspect fuses and power feeds for the ALCM; verify ignition-switched and constant power where applicable
- Visually inspect the ALCM connector and harness for corrosion, bent pins, water intrusion, or damage
- Measure power and ground at the module connector (voltage and continuity to chassis ground)
- Measure CAN_H and CAN_L voltages at the ALCM connector with ignition on
Signal parameters
- Network type: typically CAN (high-speed 500 kb/s) or vehicle-specific low-speed CAN/FlexRay; confirm vehicle network architecture
- Recessive state (no traffic): CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (both near mid-supply)
- Dominant state (bus active): CAN_H rises to ≈ 3.5 V, CAN_L falls to ≈ 1.5 V; differential ~2.0 V
- Idle voltage tolerance: ±0.5 V around 2.5 V depending on vehicle
- Termination: nominal ~60 ohms measured across CAN_H and CAN_L with key on (two 120 Ω resistors in parallel)
Diagnostic algorithm
- Connect a full-function scan tool. Verify and record U0180 and any other network codes. Note freeze-frame and module presence.
- Check battery voltage and charging (≥12.2 V at rest; ≥12.6 V key off; ≥13.5 V with engine running). Low voltage can cause comms errors.
- Verify ALCM power and ground: identify fuse(s) and measure battery voltage at module power pin(s) with key on and off. Backprobe per service data.
- Visually inspect ALCM connector and harness for corrosion, moisture, bent pins, or damage. Repair as needed and re-test communication.
- Measure CAN_H and CAN_L at the ALCM connector with key on. Compare to expected idle voltages and to a known-good node on the same bus.
- Check bus termination by measuring resistance across CAN_H and CAN_L with key off; expect ~60 ohms. Open or very low values indicate termination or short issues.
- If voltages are out of range, isolate the fault: disconnect ALCM and measure bus at harness side to determine if fault is in module or wiring. Check for short to power/ground on CAN lines.
- Perform a wiggle test on harness and connectors while monitoring communication and voltages to reproduce intermittent faults. Repair damaged wiring or connectors.
- If wiring, power and grounds are good at the connector but the module still does not respond, attempt to communicate with the module using manufacturer diagnostic procedures (module reset, wake commands, reflash if available).
- As a last step, replace the ALCM only after confirming network integrity and reprogramming the replacement module per manufacturer instructions. Clear codes and verify repair by road test and rescanning.
Likely causes
- Blown fuse or removed power to module
- Loose/corroded connector at the ALCM
- Broken or pinched CAN wires in harness near doors or front end
- Failed ALCM CAN transceiver or internal module failure
- Open/shorted CAN bus or missing termination resistor
Fault status
Status
Lost communication with Automatic Lighting Control Module. No messages received from ALCM on the vehicle network or module not responding to diagnostic requests.
Repair difficulty: Medium
Diagnostic time: 0.5-3.0 hours
Similar codes
Repair manuals
Brands with available manuals
9,032
The library contains 9,032 repair and diagnostic manuals. Choose a brand to open the full manual tree by year, model and trim.
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
Code
U0180
HYUNDAI
U — Network/User
Lost Communication With Automatic Lighting Control Module
AI status
Completed
Completed
100%
Causes
- Blown fuse or loss of module power/ignition supply
- Poor or missing ground connection to the ALCM
- Damaged, corroded, or loose connector at the ALCM
- Broken, shorted or high-resistance CAN/wiring harness between ALCM and network
- Faulty CAN transceiver inside the ALCM
- Network short (short to battery or ground) or missing bus termination
Symptoms
- Automatic headlights, daytime running lights or adaptive lighting not functioning
- Warning message or icon related to lighting or network on dash
- Multiple network communications DTCs present or other modules reporting ALCM not responding
- Intermittent operation of lighting features or lights stuck on/off
- Scan tool cannot communicate with ALCM or module does not appear in network list
What to check
- Read all network DTCs and freeze frame data with a capable scan tool; note related U-codes
- Check battery voltage (key on) and condition; low voltage can cause comms faults
- Inspect fuses and power feeds for the ALCM; verify ignition-switched and constant power where applicable
- Visually inspect the ALCM connector and harness for corrosion, bent pins, water intrusion, or damage
- Measure power and ground at the module connector (voltage and continuity to chassis ground)
- Measure CAN_H and CAN_L voltages at the ALCM connector with ignition on
Signal parameters
- Network type: typically CAN (high-speed 500 kb/s) or vehicle-specific low-speed CAN/FlexRay; confirm vehicle network architecture
- Recessive state (no traffic): CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (both near mid-supply)
- Dominant state (bus active): CAN_H rises to ≈ 3.5 V, CAN_L falls to ≈ 1.5 V; differential ~2.0 V
- Idle voltage tolerance: ±0.5 V around 2.5 V depending on vehicle
- Termination: nominal ~60 ohms measured across CAN_H and CAN_L with key on (two 120 Ω resistors in parallel)
Diagnostic algorithm
- Connect a full-function scan tool. Verify and record U0180 and any other network codes. Note freeze-frame and module presence.
- Check battery voltage and charging (≥12.2 V at rest; ≥12.6 V key off; ≥13.5 V with engine running). Low voltage can cause comms errors.
- Verify ALCM power and ground: identify fuse(s) and measure battery voltage at module power pin(s) with key on and off. Backprobe per service data.
- Visually inspect ALCM connector and harness for corrosion, moisture, bent pins, or damage. Repair as needed and re-test communication.
- Measure CAN_H and CAN_L at the ALCM connector with key on. Compare to expected idle voltages and to a known-good node on the same bus.
- Check bus termination by measuring resistance across CAN_H and CAN_L with key off; expect ~60 ohms. Open or very low values indicate termination or short issues.
- If voltages are out of range, isolate the fault: disconnect ALCM and measure bus at harness side to determine if fault is in module or wiring. Check for short to power/ground on CAN lines.
- Perform a wiggle test on harness and connectors while monitoring communication and voltages to reproduce intermittent faults. Repair damaged wiring or connectors.
- If wiring, power and grounds are good at the connector but the module still does not respond, attempt to communicate with the module using manufacturer diagnostic procedures (module reset, wake commands, reflash if available).
- As a last step, replace the ALCM only after confirming network integrity and reprogramming the replacement module per manufacturer instructions. Clear codes and verify repair by road test and rescanning.
Likely causes
- Blown fuse or removed power to module
- Loose/corroded connector at the ALCM
- Broken or pinched CAN wires in harness near doors or front end
- Failed ALCM CAN transceiver or internal module failure
- Open/shorted CAN bus or missing termination resistor
Fault status
Status
Lost communication with Automatic Lighting Control Module. No messages received from ALCM on the vehicle network or module not responding to diagnostic requests.
Repair difficulty: Medium
Diagnostic time: 0.5-3.0 hours
Similar codes
Repair manuals
Manual library for HYUNDAI
371
Browse 371 HYUNDAI manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.
HYUNDAI
-
HYUNDAI: 2023
-
Elantra
-
Elantra N
-
Kona N
-
Tucson
- Hybrid Blue
- Hybrid Limited
- Hybrid SEL Convenience
- Limited, Eng CD G4EN, 4WD
- Limited, Eng CD G4EN, FWD
- Limited, Eng CD G4KN, 4WD
- Limited, Eng CD G4KN, FWD
- N Line, Eng CD G4EN, 4WD
- N Line, Eng CD G4EN, FWD
- N Line, Eng CD G4KN, 4WD
- N Line, Eng CD G4KN, FWD
- Plug-In Hybrid Limited
- Plug-In Hybrid SEL
- SE, Eng CD G4EN, 4WD
- SE, Eng CD G4EN, FWD
- SE, Eng CD G4KN, 4WD
- SE, Eng CD G4KN, FWD
- SEL, Eng CD G4EN, 4WD
- SEL, Eng CD G4EN, FWD
- SEL, Eng CD G4KN, 4WD
- SEL, Eng CD G4KN, FWD
- XRT, Eng CD G4EN, 4WD
- XRT, Eng CD G4EN, FWD
- XRT, Eng CD G4KN, 4WD
- XRT, Eng CD G4KN, FWD
-
-
HYUNDAI: 2022
-
Elantra N
-
Kona N
-
Veloster N
-
HYUNDAI: 2021
-
Veloster N
-
HYUNDAI: 2020
-
Palisade
-
Veloster N
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email