AutoCodes – Chevrolet – U2120 Chevrolet

U2120 Chevrolet Code - Lost Communication With Dynamic Headlamp Leveling Device

Quick Answer

Devices connected to the serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Dynamic Headlamp Leveling (DHL) Device, Dynamic Headlamp Leveling Device harness is open or shorted, Dynamic Headlamp Leveling Device 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: U2120 Chevrolet indicates Lost Communication With Dynamic Headlamp Leveling Device.
Common causes: Common causes include Faulty Dynamic Headlamp Leveling (DHL) Device, Dynamic Headlamp Leveling Device harness is open or shorted, Dynamic Headlamp Leveling Device 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.

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Code Popularity 772

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 16, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U2120 Chevrolet Description

Devices connected to the serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the devices. The devices have prerecorded information about what messages are needed to be exchanged on the serial data circuits, for each virtual network. The messages are supervised and also, some periodic messages are used by the receiver device as an availability indication of the transmitter device. Each message contains the identification number of the transmitter device. A loss of serial data communications Diagnostic Trouble Code (DTC) does not represent a failure of the devices that contain the stored code. The DTC will set when a supervised periodic message that includes the transmitter device availability has not been received.

OBDII Code U2120 Chevrolet - Lost Communication With Dynamic Headlamp Leveling Device - AutoCodes.com — U2120 Chevrolet Code - Lost Communication With Dynamic Headlamp Leveling Device

What does this mean?

What are the Possible Causes of the DTC U2120 Chevrolet?

Faulty Dynamic Headlamp Leveling (DHL) Device
Dynamic Headlamp Leveling Device harness is open or shorted
Dynamic Headlamp Leveling Device circuit poor electrical connection

How to Fix the DTC U2120 Chevrolet?

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 U2120 Chevrolet 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.

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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.

Frequently Asked Questions about U2120 Chevrolet Code

1. What are the common symptoms of OBDII code U2120 (Lost Communication With Dynamic Headlamp Leveling Device) in a Chevrolet?

- Dim or misaligned headlights, dashboard warning light, and headlight leveling system malfunction are common symptoms.

2. What are the possible causes of OBDII code U2120 in a Chevrolet?

- Potential causes include a faulty headlamp leveling control module, damaged wiring harness, loose connections, or a malfunctioning headlamp leveling sensor.

3. How can I diagnose OBDII code U2120 in my Chevrolet?

- A thorough inspection of the headlamp leveling system, checking the wiring connections, and using a diagnostic scanner to read the trouble codes can help diagnose the issue.

4. Can I still drive my Chevrolet with OBDII code U2120 present?

- It is generally safe to drive with this code, but it is recommended to address the issue promptly to ensure proper headlight functionality and visibility.

5. What repairs are typically needed to fix OBDII code U2120 in a Chevrolet?

- Repair options may include replacing the headlamp leveling control module, repairing or replacing damaged wiring, fixing loose connections, or recalibrating the headlamp leveling system.

6. Is it possible to reset OBDII code U2120 in a Chevrolet without addressing the underlying issue?

- While clearing the trouble code may temporarily eliminate the dashboard warning light, the issue causing the code will persist unless properly diagnosed and repaired.

7. Can extreme weather conditions affect the occurrence of OBDII code U2120 in a Chevrolet?

- Extreme temperatures or moisture exposure can potentially impact the headlamp leveling system components and contribute to the communication error indicated by the code.

8. How much does it typically cost to repair OBDII code U2120 in a Chevrolet?

- Repair costs can vary depending on the specific issue, parts needed, labor rates, and whether the repair is done at a dealership or an independent repair shop.

9. Are there any preventive measures to avoid OBDII code U2120 in a Chevrolet?

- Regular inspection and maintenance of the headlamp leveling system, keeping connections clean and secure, and addressing any headlight alignment issues promptly can help prevent this code from appearing.

10. Can a DIY enthusiast with basic automotive knowledge fix OBDII code U2120 in a Chevrolet?

- Depending on the specific cause of the code, some DIY repairs like checking and securing connections or replacing a sensor may be feasible for those with basic automotive skills and the right tools.