AutoCodes – Generic – U1523

U1523 Code - Headlamp Control Module/Headlamp Leveling Control Module Lost Communication With Left Headlamp On LIN Bus

Quick Answer

The Local Interconnect Network (LIN) Bus consists of a single wire with a transmission rate of 10.417 Kbit/s. Common causes include Faulty Left Headlamp, Left Headlamp harness is open or shorted, Left Headlamp circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: U1523 indicates Headlamp Control Module/Headlamp Leveling Control Module Lost Communication With Left Headlamp On LIN Bus.
Common causes: Common causes include Faulty Left Headlamp, Left Headlamp harness is open or shorted, Left Headlamp circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 4,906

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 03, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code U1523 Description

The Local Interconnect Network (LIN) Bus consists of a single wire with a transmission rate of 10.417 Kbit/s. The serial data is transmitted over a LIN circuit between a master control module and other LIN devices within a particular subsystem. If serial data communication is lost between any of the LIN devices on the LIN bus network, the master control module will set a no communication code against the non-communicating LIN device. The Diagnostic Trouble Code (DTC) will set when a supervised periodic message to the Headlamp Control Module/Headlamp Leveling Control Module from the Left Headlamp has not been received.

OBDII Code U1523 - Headlamp Control Module/Headlamp Leveling Control Module Lost Communication With Left Headlamp On LIN Bus - AutoCodes.com — U1523 Code - Headlamp Control Module/Headlamp Leveling Control Module Lost Communication With Left Headlamp On LIN Bus

What does this mean?

What are the Possible Causes of the DTC U1523?

Faulty Left Headlamp
Left Headlamp harness is open or shorted
Left Headlamp circuit poor electrical connection
Faulty Headlamp Control Module/Headlamp Leveling Control Module

How to Fix the DTC U1523?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the U1523 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the U1523 code?

Need more information on how to fix the U1523 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U1523 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

U1523 Buick — Headlamp Control Module/Headlamp Leveling Control Module Lost Communication With Left Headlamp On LIN Bus
U1523 Cadillac — Headlamp Control Module/Headlamp Leveling Control Module Lost Communication With Left Headlamp On LIN Bus
U1523 Chevrolet — Headlamp Control Module/Headlamp Leveling Control Module Lost Communication With Left Headlamp On LIN Bus
U1523 GMC — Headlamp Control Module/Headlamp Leveling Control Module Lost Communication With Left Headlamp On LIN Bus

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.