AutoCodes – Buick – B0985 Buick

B0985 Buick Code - Right Headlamp Light Distribution Shutter Control Circuit Malfunction

Quick Answer

Battery positive voltage is applied to the headlamp control module at all times. Common causes include Faulty Right Headlamp Assembly, Right Headlamp Assembly harness is open or shorted, Right Headlamp Assembly 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: B0985 Buick indicates Right Headlamp Light Distribution Shutter Control Circuit Malfunction.
Common causes: Common causes include Faulty Right Headlamp Assembly, Right Headlamp Assembly harness is open or shorted, Right Headlamp Assembly 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.

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Code Popularity 942

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 11, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B0985 Buick Description

Battery positive voltage is applied to the headlamp control module at all times. The headlamp control module has a normal operational voltage range of about 12.5-16 V and is only fully functional with the ignition switch is in the RUN position and the headlamp switch in the AUTO position. The communications enable signal from the Body Control Module (BCM) wakes the headlamp control module microprocessor. The headlamp control module receives serial data messages from the Engine Control Module (ECM), Transmission Control Module (TCM), Electronic Brake Control Module (EBCM), and BCM with information regarding power mode, speed, steering angle, transmission gear selection, and headlamp switch status. The headlamp control module calculates the headlamp angle and sends commands to the left and right adaptive forward lighting system headlamp actuators. The headlamp actuators drive the headlamps to the position commanded by the headlamp control module. The headlamp control module monitors the headlamp actuator motor control circuits for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a DTC will be stored in memory and the driver will be notified with a message displayed over the driver information center located on the instrument cluster.

OBDII Code B0985 Buick - Right Headlamp Light Distribution Shutter Control Circuit Malfunction - AutoCodes.com — B0985 Buick Code - Right Headlamp Light Distribution Shutter Control Circuit Malfunction

What does this mean?

What are the Possible Causes of the DTC B0985 Buick?

Faulty Right Headlamp Assembly
Right Headlamp Assembly harness is open or shorted
Right Headlamp Assembly circuit poor electrical connection

How to Fix the DTC B0985 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.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B0985 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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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 B0985 Buick Code

1. What does the OBDII code B0985 mean on a Buick?

B0985 indicates a malfunction in the Right Headlamp Light Distribution Shutter Control Circuit, which affects the proper functioning of the right headlampâ€™s adaptive or high-beam control.

2. What are the common symptoms of the B0985 code?

Symptoms may include the right headlamp failing to adjust its beam pattern, flickering, staying stuck in one position, or not switching between high and low beams.

3. What causes the B0985 code to appear on a Buick?

Common causes include a faulty shutter motor, wiring or connector issues in the shutter control circuit, or a malfunctioning headlamp control module.

4. Can I drive my Buick with the B0985 code active?

While you can drive, your visibility may be reduced, especially at night. Itâ€™s recommended to address the issue promptly to ensure proper headlamp performance.

5. How can I diagnose the B0985 code on my Buick?

Start by visually inspecting the right headlamp assembly, checking for damaged wiring or loose connectors. Use a scan tool to monitor the shutter motorâ€™s operation and test the circuit for continuity.

6. What tools are required to fix the B0985 code?

You may need a multimeter to check electrical connections, a scan tool to clear the code and test components, and basic hand tools for headlamp or wiring repairs.

7. How much does it cost to repair the B0985 code on a Buick?

Repair costs vary based on the issue, but replacing a shutter motor can cost $150â€“$300, while wiring repairs are typically less expensive.

8. Can a bad fuse cause the B0985 code?

Yes, if the fuse related to the headlamp or shutter control circuit is blown, it can trigger the B0985 code. Check and replace the fuse if necessary.

9. Does the B0985 code require replacing the entire headlamp assembly?

Not always. If the issue is limited to the shutter motor or wiring, these components can often be repaired or replaced without replacing the entire assembly.

10. Will clearing the B0985 code fix the problem?

Clearing the code without addressing the underlying issue will only temporarily remove the code. The problem must be repaired to prevent the code from returning.