AutoCodes – Chevrolet – B2645 2018 Chevrolet Silverado

B2645 2018 Chevrolet Silverado Code - Ambient Light Sensor Circuit

Quick Answer

The ambient light sensor is used to monitor outside lighting conditions. Common causes include Faulty Ambient Light/Sunload Sensor, Ambient Light/Sunload Sensor harness is open or shorted, Ambient Light/Sunload Sensor 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: B2645 2018 Chevrolet Silverado indicates Ambient Light Sensor Circuit.
Common causes: Common causes include Faulty Ambient Light/Sunload Sensor, Ambient Light/Sunload Sensor harness is open or shorted, Ambient Light/Sunload Sensor 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 267

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 May 29, 2023

Description
Possible Causes
How To Fix
Tech Notes ▶
Cost to Diagnose
FAQs
Comments
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Code B2645 2018 Chevrolet Silverado Description

The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 0.2 and 4.9 V depending on outside lighting conditions. The Body Control Module (BCM) provides a 5 V reference signal to the ambient light sensor and the Heating, Ventilation, and Air Conditioning (HVAC) control module provides a low reference ground. The BCM monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either Daytime Running Lights (DRL) or automatic lamp control when the headlamp switch is in the AUTO position. In daylight conditions, the BCM will command the daytime running lamps ON. During low light conditions, the BCM will command the low beam headlamps ON. Any function or condition that turns on the headlamps will cancel daytime running lamps operation.

OBDII Code B2645 2018 Chevrolet Silverado - Ambient Light Sensor Circuit - AutoCodes.com — B2645 2018 Chevrolet Silverado Code - Ambient Light Sensor Circuit

What does this mean?

What are the Possible Causes of the DTC B2645 2018 Chevrolet Silverado?

Faulty Ambient Light/Sunload Sensor
Ambient Light/Sunload Sensor harness is open or shorted
Ambient Light/Sunload Sensor circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B2645 2018 Chevrolet Silverado?

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 does this mean?

Code Tech Notes

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B2645 2018 Chevrolet Silverado 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 B2645 2018 Chevrolet Silverado Code

1. What does the OBDII code B2645 mean on a 2018 Chevrolet Silverado?

Code B2645 indicates an issue with the Ambient Light Sensor Circuit, which monitors exterior light levels for automatic headlight operation.

2. What are the symptoms of a B2645 code in a 2018 Chevrolet Silverado?

Common symptoms include malfunctioning automatic headlights, the headlights staying on or off at inappropriate times, or a dashboard warning light.

3. What causes the B2645 code to appear?

Potential causes include a faulty ambient light sensor, damaged wiring or connectors in the sensor circuit, or a malfunctioning body control module (BCM).

4. How do you diagnose a B2645 code?

Diagnosis involves using a scan tool to confirm the code, inspecting the ambient light sensor for physical damage, testing the wiring and connectors for continuity, and checking the BCM for related issues.

5. Can a faulty ambient light sensor trigger the B2645 code?

Yes, a defective or malfunctioning ambient light sensor is one of the most common reasons for this code.

6. How do you fix the B2645 code on a 2018 Chevrolet Silverado?

Repairs may include replacing the ambient light sensor, repairing or replacing damaged wiring or connectors, or reprogramming or replacing the body control module if necessary.

7. Is it safe to drive with the B2645 code active?

Yes, the vehicle is generally safe to drive, but you may experience issues with automatic headlight functionality, which could impact visibility in changing light conditions.

8. Where is the ambient light sensor located on a 2018 Chevrolet Silverado?

The ambient light sensor is typically located on the dashboard near the windshield, where it can detect exterior light levels.

9. How much does it cost to repair a B2645 code?

Repair costs can vary, but replacing an ambient light sensor usually ranges from $100 to $300, including parts and labor. Wiring or BCM issues may cost more.

10. Can a B2645 code be cleared without repairs?

The code can be temporarily cleared with a scan tool, but if the underlying issue isnâ€™t resolved, the code will likely return.