AutoCodes – GMC – B2647 GMC

B2647 GMC Code - Ambient Light Sensor Circuit

Quick Answer

The Body Control Module (BCM) monitors the Ambient Light Sensor signal circuit in order to determine if the Daytime Running Lights (DRL) or the Auto Headlights (ALC) should be turned ON in the AUTO mode. Common causes include Faulty Ambient Light Sensor, Ambient Light Sensor harness is open or shorted, Ambient Light 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
B2647 GMC indicates Ambient Light Sensor Circuit.
Common causes
Common causes include Faulty Ambient Light Sensor, Ambient Light Sensor harness is open or shorted, Ambient Light 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.
AI answers can be wrong. Verify repairs with testing. Open full chat
Code Popularity 2,254
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Jan 09, 2020
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Code B2647 GMC Description

The Body Control Module (BCM) monitors the Ambient Light Sensor signal circuit in order to determine if the Daytime Running Lights (DRL) or the Auto Headlights (ALC) should be turned ON in the AUTO mode. When the BCM senses the ambient light sensor signal voltage is between 1.75-4.9 volts, either the DRL will be commanded ON or the ALC will be commanded ON depending upon the amount of light received by the sensor.
OBDII Code B2647 GMC - Ambient Light Sensor Circuit - AutoCodes.com
B2647 GMC Code - Ambient Light Sensor Circuit

What are the Possible Causes of the DTC B2647 GMC?

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

How to Fix the DTC B2647 GMC?

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 B2647 GMC 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 B2647 GMC code?

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Need Help with the Code?

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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 B2647 GMC Code

1. What are the common symptoms of OBDII code B2647 GMC Ambient Light Sensor Circuit?

Symptoms may include erratic behavior of automatic headlights, dimming or brightening of interior lights unexpectedly, or malfunctioning ambient light sensor readings.

2. What are the possible causes of OBDII code B2647 GMC Ambient Light Sensor Circuit?

Causes may include a faulty ambient light sensor, damaged wiring or connections in the ambient light sensor circuit, or a malfunctioning body control module.

3. How can I diagnose the Ambient Light Sensor Circuit issue related to code B2647 GMC?

Diagnosis involves checking the ambient light sensor for physical damage, inspecting the wiring for any signs of wear or corrosion, and using a diagnostic scanner to read the code and sensor data.

4. Can I repair the Ambient Light Sensor Circuit issue causing code B2647 GMC myself?

If you have experience working with automotive wiring and electrical systems, you may be able to repair the issue. However, it's recommended to consult a professional mechanic for accurate diagnosis and repair.

5. Are there any simple fixes I can try before taking my vehicle to a mechanic for OBDII code B2647 GMC?

You can start by checking the ambient light sensor for any visible damage, ensuring the sensor is clean and unobstructed, and inspecting the wiring connections for any loose or corroded contacts.

6. How critical is it to address OBDII code B2647 GMC Ambient Light Sensor Circuit promptly?

While the issue may not directly affect the drivability of your vehicle, ignoring it can lead to inconvenience such as non-functioning automatic lighting systems or inaccurate ambient light readings.

7. Can a malfunctioning Ambient Light Sensor Circuit cause other problems in my GMC vehicle?

A malfunctioning ambient light sensor circuit may affect other systems that rely on ambient light data, such as automatic headlights, interior lighting controls, and climate control systems.

8. Will resetting the OBDII code B2647 GMC resolve the Ambient Light Sensor Circuit issue?

Resetting the code may temporarily clear the error message, but it won't fix the underlying problem with the ambient light sensor circuit. It's crucial to address the root cause for a permanent solution.

9. How long does it typically take to repair the Ambient Light Sensor Circuit problem associated with code B2647 GMC?

The repair time can vary depending on the exact cause of the issue. Simple fixes like cleaning connections may take a short time, while replacing a faulty sensor or repairing wiring could require more extensive work.

10. Is it safe to continue driving my GMC vehicle with OBDII code B2647 related to the Ambient Light Sensor Circuit?

If the only symptom is related to ambient light sensing functions, it should be safe to drive your vehicle. However, it's recommended to address the issue promptly to avoid potential complications and ensure proper functionality of related systems.

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