B3920 Buick Code - Seat Motors Group 1 Common Circuit
Quick Answer
The Seat Memory Control Module controls the seat, lumbar, and adjustable pedal motors via half bridges that are connected to power rails internal to the module. Common causes include Faulty Seat, Lumbar, or Adjustable Pedal Motors, Seat, Lumbar, or Adjustable Pedal Motors harness is open or shorted, Seat, Lumbar, or Adjustable Pedal Motors 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
- B3920 Buick indicates Seat Motors Group 1 Common Circuit.
- Common causes
- Common causes include Faulty Seat, Lumbar, or Adjustable Pedal Motors, Seat, Lumbar, or Adjustable Pedal Motors harness is open or shorted, Seat, Lumbar, or Adjustable Pedal Motors 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 B3920 Buick Description
When a power seat, lumbar, or adjustable pedal switch is pressed or when a memory recall is requested, each seat motor receives battery voltage and ground from the seat memory control module via the motor control circuits. All motors are reversible, so the direction the motor rotates depends on which control circuit voltage is applied and which control circuit ground is applied. When the switch is operated in the opposite direction, the module reverses the polarity and applies voltage and ground to the opposite circuits to move the seat in the opposite direction.
The Diagnostic Trouble Code (DTC) sets when the voltage on any power rail 1 motor control circuit exceeds 2.78 volts for 100 ms or is below 1.47 volts for 100 ms.
What are the Possible Causes of the DTC B3920 Buick?
- Faulty Seat, Lumbar, or Adjustable Pedal Motors
- Seat, Lumbar, or Adjustable Pedal Motors harness is open or shorted
- Seat, Lumbar, or Adjustable Pedal Motors circuit poor electrical connection
- Faulty Seat Memory Control Module
How to Fix the DTC B3920 Buick?
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.
Code Tech Notes
B3920 02 Group 1 Seat Motors Circuit Shorted to Ground
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the B3920 Buick 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 B3920 Buick Code
1. What does the OBDII code B3920 mean on a Buick?
The code B3920 indicates an issue in the Seat Motors Group 1 Common Circuit, which typically involves the wiring or components controlling seat adjustments.
2. What are the common symptoms of the B3920 code?
Symptoms may include inoperative seat adjustments, slow or jerky seat movement, and unusual noises when trying to adjust the seat.
3. What causes the B3920 code to appear in a Buick?
Common causes include damaged seat motor wiring, faulty seat adjustment motors, corroded connectors, or a malfunctioning seat control module.
4. Can I still drive my Buick if the B3920 code is active?
Yes, the vehicle is still drivable, but seat adjustment functionality may be limited or completely inoperative, which could affect comfort and safety.
5. How do I diagnose the B3920 code on my Buick?
Diagnosis typically involves checking the seat motor wiring and connectors for damage or corrosion, verifying power and ground at the motor, and testing the seat control module.
6. How is the B3920 code fixed in a Buick?
Repairs may include replacing damaged wiring, cleaning or replacing corroded connectors, or replacing a faulty seat motor or seat control module.
7. What tools are needed to troubleshoot the B3920 code?
A diagnostic scan tool, multimeter, and basic hand tools are commonly required to diagnose and repair this issue.
8. Can a blown fuse cause the B3920 code?
Yes, a blown fuse in the seat motor circuit can trigger this code by interrupting power to the seat adjustment system.
9. How much does it cost to fix the B3920 code on a Buick?
Repair costs vary depending on the specific issue but can range from $50 for minor wiring repairs to $500 or more for replacing seat motors or control modules.
10. Can I clear the B3920 code without fixing the issue?
Clearing the code with a scan tool may temporarily remove it, but the code will likely return if the underlying problem is not addressed.
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