B1840 2017 GMC Sierra Code - Driver Seat Lumbar Up Switch Circuit
Quick Answer
The Seat Memory Control Module supplies a reference voltage to each signal circuit of the Driver Seat Adjuster Switch. Common causes include Faulty Driver Seat Adjuster Switch, Driver Seat Adjuster Switch harness is open or shorted, Driver Seat Adjuster Switch 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
- B1840 2017 GMC Sierra indicates Driver Seat Lumbar Up Switch Circuit.
- Common causes
- Common causes include Faulty Driver Seat Adjuster Switch, Driver Seat Adjuster Switch harness is open or shorted, Driver Seat Adjuster Switch 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.
Code B1840 2017 GMC Sierra Description
What are the Possible Causes of the DTC B1840 2017 GMC Sierra?
- Faulty Driver Seat Adjuster Switch
- Driver Seat Adjuster Switch harness is open or shorted
- Driver Seat Adjuster Switch circuit poor electrical connection
- Faulty Seat Memory Control Module
How to Fix the DTC B1840 2017 GMC Sierra?
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 B1840 2017 GMC Sierra 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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Frequently Asked Questions about B1840 2017 GMC Sierra Code
1. What does the OBDII code B1840 mean on a 2017 GMC Sierra?
The B1840 code indicates an issue in the driver seat lumbar up switch circuit, which affects the lumbar support adjustment functionality.
2. What are the common symptoms of code B1840 in a GMC Sierra?
Symptoms include the driver seat lumbar support not moving upward, intermittent or unresponsive lumbar controls, or erratic lumbar adjustment behavior.
3. What causes the B1840 code to appear?
Common causes include a faulty lumbar up switch, damaged wiring or connectors in the circuit, or a malfunctioning seat control module.
4. How is the B1840 code diagnosed?
Diagnosis involves inspecting the lumbar switch, checking the wiring and connectors for damage or corrosion, and testing the seat control module for proper operation.
5. Can I still drive my GMC Sierra with the B1840 code?
Yes, the vehicle is still drivable, but the driver seat lumbar support adjustment may not function properly, potentially affecting comfort.
6. How do you fix the B1840 code on a 2017 GMC Sierra?
Repairs can include replacing the lumbar up switch, repairing damaged wiring or connectors, or reprogramming or replacing the seat control module if needed.
7. How much does it cost to repair the B1840 code issue?
The repair cost varies but may range from $50 to $300 depending on whether only the switch or wiring needs repair or if the seat control module requires replacement.
8. Can a blown fuse cause the B1840 code in a GMC Sierra?
While unlikely, a blown fuse for the seat adjustment system could contribute to the problem and should be checked during diagnostics.
9. Is resetting the code enough to fix the B1840 issue?
Resetting the code may clear it temporarily, but the underlying issue must be fixed to prevent the code from returning.
10. Can the B1840 code be caused by normal wear and tear?
Yes, over time, the lumbar adjustment switch or wiring may wear out or become faulty, leading to this code.
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