AutoCodes – Buick – B3801 Buick

B3801 Buick Code - Passenger Compartment Lamp Request Circuit

Quick Answer

The Body Control Module (BCM) monitors the courtesy lamp switch signal circuit in order to determine when the courtesy/dome lamps should be illuminated. Common causes include Faulty Headlamp Switch, Headlamp Switch harness is open or shorted, Headlamp 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: B3801 Buick indicates Passenger Compartment Lamp Request Circuit.
Common causes: Common causes include Faulty Headlamp Switch, Headlamp Switch harness is open or shorted, Headlamp 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.

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Code Popularity 440

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 17, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B3801 Buick Description

The Body Control Module (BCM) monitors the courtesy lamp switch signal circuit in order to determine when the courtesy/dome lamps should be illuminated. When the BCM senses that the courtesy lamp switch signal circuit is grounded when the switch is activated, the BCM will illuminate the courtesy/dome lamps. The Diagnostic Trouble Code (DTC) sets when the BCM instrument panel dimmer switch reference voltage must be between 4.5-5.5 volts.

OBDII Code B3801 Buick - Passenger Compartment Lamp Request Circuit - AutoCodes.com — B3801 Buick Code - Passenger Compartment Lamp Request Circuit

What does this mean?

What are the Possible Causes of the DTC B3801 Buick?

Faulty Headlamp Switch
Headlamp Switch harness is open or shorted
Headlamp Switch circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B3801 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 B3801 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.

Need more information about the B3801 Buick code?

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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 B3801 Buick Code

What does the OBDII code B3801 mean for a Buick?

B3801 indicates a malfunction in the Passenger Compartment Lamp Request Circuit, which is responsible for controlling the interior lights when a door is opened or when the vehicle is unlocked.

What are common symptoms of the B3801 code?

Common symptoms include interior lights that do not turn on when doors are opened, lights that stay on continuously, or intermittent lighting issues in the passenger compartment.

What could cause the B3801 code to trigger?

Possible causes include a faulty door switch, a defective passenger compartment lamp, wiring issues, or a malfunctioning body control module (BCM).

How can I diagnose the B3801 code?

To diagnose B3801, check the door switches for proper operation, inspect the wiring for damage or corrosion, and test the BCM for faults. A scan tool can help confirm the code and check for related codes.

What repairs are typically needed for a B3801 code?

Repairs may involve replacing faulty door switches, repairing or replacing damaged wiring, or in some cases, replacing the body control module.

Can I clear the B3801 code myself?

Yes, you can clear the B3801 code using an OBDII scanner, but itâ€™s important to address the underlying issue to prevent the code from returning.

Will the B3801 code affect my vehicle's performance?

While the B3801 code primarily affects the interior lighting system, it does not typically impact the overall performance of the vehicle.

Is it safe to drive with a B3801 code?

Yes, it is generally safe to drive with a B3801 code, but you may experience inconvenience due to non-functioning interior lights.

How much does it typically cost to fix the B3801 code?

Repair costs can vary widely depending on the cause of the issue, ranging from a simple switch replacement costing around $50 to more complex repairs involving the BCM, which could exceed $200.