B1985 – OBD-II DTC

OBD-II DTC B1985 – Seat Switch Lumbar Deflate Circuit Failure

DTC B1985 meaning

DTC B1985 refers to a diagnostic trouble code indicating a failure in the seat switch lumbar deflate circuit. This code is part of the On-Board Diagnostics II (OBD-II) system, which monitors various vehicle components and systems for faults. The lumbar support system in the seat is designed to provide comfort and support to the driver and passengers, and this code suggests that there is an issue with the circuit responsible for deflating the lumbar support.

DTC B1985 symptoms

Common symptoms associated with DTC B1985 may include:

• Inability to adjust the lumbar support in the seat.
• Warning lights illuminated on the dashboard, particularly the airbag or seatbelt warning lights.
• Unusual noises from the seat when attempting to adjust the lumbar support.
• Seat comfort issues due to improper lumbar support adjustment.

DTC B1985 causes

Several factors can lead to the triggering of DTC B1985, including:

• Faulty seat switch or lumbar support switch.
• Wiring issues, such as damaged or corroded wires in the lumbar deflate circuit.
• Defective lumbar support actuator or motor.
• Faulty body control module (BCM) that manages the seat functions.
• Poor electrical connections or ground issues in the circuit.

DTC B1985 seriousness

DTC B1985 is considered a moderate issue. While it may not affect the vehicle’s drivability, it can impact the comfort of the driver and passengers. Additionally, if the code is related to the airbag system, it may pose a safety risk, as the airbag system may not function properly in the event of a collision.

How to diagnose DTC B1985

To diagnose DTC B1985, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the DTC B1985.
2. Inspect the seat switch and lumbar support switch for any visible damage or wear.
3. Check the wiring and connectors in the lumbar deflate circuit for signs of corrosion or damage.
4. Test the lumbar support actuator or motor for proper operation.
5. Examine the body control module (BCM) for any faults or issues.
6. Clear the DTC and perform a function test to see if the code returns.

How to fix DTC B1985 step-by-step instructions

To fix DTC B1985, follow these steps:

1. Start by inspecting the seat switch and lumbar support switch for any signs of damage. Replace if necessary.
2. Examine the wiring and connectors in the lumbar deflate circuit. Repair or replace any damaged wires or connectors.
3. Test the lumbar support actuator or motor using a multimeter to ensure it is functioning correctly. Replace if faulty.
4. Check the body control module (BCM) for any software updates or faults. Reprogram or replace if needed.
5. After making repairs, reconnect all components and ensure proper connections.
6. Clear the DTC using an OBD-II scanner and perform a function test to verify that the issue is resolved.

How to erase DTC B1985

To erase DTC B1985, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn on the vehicle’s ignition without starting the engine.
3. Navigate to the “Erase Codes” or “Clear DTCs” option on the scanner.
4. Confirm the action to clear the trouble codes.
5. Disconnect the scanner and turn off the ignition.
6. Start the vehicle and check if the DTC reappears during a function test.

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