Engine-CodesGMC – B1840 2016 GMC Sierra

B1840 2016 GMC Sierra Code - Driver Seat Lumbar Up Switch Circuit

Quick Answer

The B1840 code for a 2016 GMC Sierra specifically refers to an issue with the driver seat lumbar up switch circuit. Common causes include Faulty driver seat lumbar up switch, Wiring issues in the circuit connecting the switch to the lumbar support system, Loose or damaged electrical connections. 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
B1840 2016 GMC Sierra indicates Driver Seat Lumbar Up Switch Circuit.
Common causes
Common causes include Faulty driver seat lumbar up switch, Wiring issues in the circuit connecting the switch to the lumbar support system, Loose or damaged electrical connections.
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.
Table of contents Created and updated by William Orellana on Sep 11, 2024
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Code B1840 2016 GMC Sierra Description

The B1840 code for a 2016 GMC Sierra specifically refers to an issue with the driver seat lumbar up switch circuit. This code indicates that there is a malfunction in the circuit responsible for controlling the lumbar support adjustment in the driver's seat. The lumbar support feature is designed to provide additional lower back support and improve overall comfort while driving. When this circuit is not functioning properly, it can affect the driver's seating position and comfort level.

OBDII Code B1840 2016 GMC Sierra - Driver Seat Lumbar Up Switch Circuit
B1840 2016 GMC Sierra Code - Driver Seat Lumbar Up Switch Circuit

Common Causes of B1840 2016 GMC Sierra

  1. Faulty driver seat lumbar up switch.
  2. Wiring issues in the circuit connecting the switch to the lumbar support system.
  3. Loose or damaged electrical connections.
  4. Malfunctioning lumbar support motor.
  5. Defective control module for the lumbar support system.

Symptoms of B1840 2016 GMC Sierra

  1. Inability to adjust the lumbar support in the driver's seat.
  2. Unexpected movement or lack of movement in the lumbar support.
  3. Uncomfortable seating position while driving.
  4. Lumbar support adjustment buttons not responding.

How to Fix B1840 2016 GMC Sierra

  1. Begin by diagnosing the specific cause of the issue using a diagnostic tool to pinpoint the exact source of the problem.
  2. Inspect the driver seat lumbar up switch and wiring for any visible damage or loose connections. Replace or repair as necessary.
  3. Test the lumbar support motor to ensure it is functioning correctly. Replace if it is found to be faulty.
  4. Check the control module for the lumbar support system and replace if it is malfunctioning.
  5. Clear the diagnostic trouble codes from the vehicle's system and test the driver seat lumbar support to ensure it is functioning properly.

Cost to Fix B1840 2016 GMC Sierra

The typical repair costs for addressing a B1840 code related to the driver seat lumbar up switch circuit in a 2016 GMC Sierra can vary depending on the specific cause of the issue. On average, parts for this repair may range from $100 to $300, while labor costs can range from $80 to $150 per hour. The total cost of the repair can vary based on the extent of the issue and the time required to diagnose and resolve it. It is recommended to consult with a professional mechanic or auto repair shop for a more accurate cost estimate based on the specific circumstances of the vehicle.

Tech Notes for B1840 2016 GMC Sierra









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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 B1840 2016 GMC Sierra Code

1. What are the common symptoms of OBDII code B1840 in a 2016 GMC Sierra related to the driver seat lumbar up switch circuit?

- The common symptoms include the driver seat lumbar up switch not functioning properly, the seat lumbar support being stuck in one position, or the seat lumbar support moving uncontrollably.

2. What are the possible causes of OBDII code B1840 in a 2016 GMC Sierra?

- The possible causes could be a malfunctioning driver seat lumbar up switch, damaged wiring or connectors in the circuit, or a faulty seat control module.

3. How can I diagnose the issue related to OBDII code B1840 in my 2016 GMC Sierra?

- You can start by checking the wiring and connectors for any visible damage, testing the driver seat lumbar up switch for proper functionality, and using a diagnostic scanner to read and clear the trouble code.

4. Is it safe to continue driving my 2016 GMC Sierra with OBDII code B1840 related to the driver seat lumbar up switch circuit?

- It is not recommended to drive the vehicle with this issue as it may affect the driver's comfort and seating position, potentially leading to discomfort or distraction while driving.

5. How can I repair OBDII code B1840 in my 2016 GMC Sierra related to the driver seat lumbar up switch circuit?

- The repair process may involve replacing the driver seat lumbar up switch, repairing or replacing damaged wiring and connectors, or reprogramming the seat control module if necessary.

6. Can I fix OBDII code B1840 in my 2016 GMC Sierra related to the driver seat lumbar up switch circuit myself?

- Depending on your automotive repair skills and knowledge, you may be able to troubleshoot and fix the issue yourself by following the vehicle's service manual or seeking assistance from a professional mechanic.

7. Are there any temporary solutions to address OBDII code B1840 in my 2016 GMC Sierra related to the driver seat lumbar up switch circuit?

- One temporary solution could be manually adjusting the seat lumbar support to a comfortable position and avoiding using the malfunctioning switch until the issue is properly diagnosed and repaired.

8. How much does it typically cost to repair OBDII code B1840 in a 2016 GMC Sierra related to the driver seat lumbar up switch circuit?

- The cost of repair can vary depending on the specific cause of the issue, the cost of replacement parts, and the labor rates of the repair shop. It is recommended to obtain quotes from different professionals for an accurate estimate.

9. Are there any recalls or technical service bulletins related to OBDII code B1840 in a 2016 GMC Sierra?

- It is advisable to check with a GMC dealership or visit the National Highway Traffic Safety Administration (NHTSA) website to see if there are any recalls or technical service bulletins related to this specific OBDII code in your vehicle.

10. How can I prevent OBDII code B1840 from occurring again in my 2016 GMC Sierra after repair?

- To prevent the recurrence of this issue, it is essential to ensure proper installation of replacement parts, regularly inspect the seat lumbar switch circuit for any signs of damage, and follow the manufacturer's maintenance recommendations for your vehicle.

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