AutoCodes – Cadillac – B3801 Cadillac

B3801 Cadillac 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 Cadillac 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 544

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
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

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

What does this mean?

What are the Possible Causes of the DTC B3801 Cadillac?

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 Cadillac?

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 Cadillac 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 Cadillac code?

Need more information on how to fix the B3801 Cadillac code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B3801 Cadillac code diagnosed by a professional: Find a repair shop in your area

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 Cadillac Code

1. What are the common symptoms of OBDII code B3801 Cadillac related to the Passenger Compartment Lamp Request Circuit?

- The common symptoms include the interior lights not turning on when the doors are opened or the switch is activated.

2. What could be the potential causes of OBDII code B3801 in a Cadillac, specifically related to the Passenger Compartment Lamp Request Circuit?

- Possible causes may include a faulty interior lamp switch, a wiring issue, a blown fuse, or a malfunctioning Body Control Module (BCM).

3. How can I diagnose the OBDII code B3801 in my Cadillac?

- You can start by checking the interior lamp switch for proper operation, inspecting the wiring for any damage, testing the fuse related to the interior lights, and using a scan tool to communicate with the BCM for diagnostic trouble codes.

4. Is it safe to continue driving my Cadillac with OBDII code B3801 unresolved?

- While the issue may not affect the overall drivability of the vehicle, it is recommended to address the problem promptly to ensure proper functionality of the interior lighting system.

5. Can I repair OBDII code B3801 Cadillac related to the Passenger Compartment Lamp Request Circuit myself?

- Depending on your skill level and access to tools, you may be able to troubleshoot and repair the issue yourself by following the diagnostic steps outlined in the service manual or seeking assistance from a professional technician.

6. What are some tips for repairing OBDII code B3801 in a Cadillac?

- Some repair tips include checking and replacing the interior lamp switch if necessary, inspecting and repairing any damaged wiring, ensuring the fuse is intact, and resetting the BCM after making repairs.

7. Will resetting the BCM resolve OBDII code B3801 in a Cadillac?

- Resetting the BCM may clear the diagnostic trouble code temporarily, but if the underlying issue such as a faulty switch or wiring problem persists, the code is likely to return.

8. How much can I expect to pay to fix OBDII code B3801 related to the Passenger Compartment Lamp Request Circuit in a Cadillac?

- The cost of repair can vary depending on the specific cause of the issue and whether you choose to address it yourself or seek professional help. Costs may range from a few dollars for a fuse replacement to a few hundred dollars for more complex repairs.

9. Are there any recalls or technical service bulletins related to OBDII code B3801 in Cadillac vehicles?

- It's advisable to check with your local Cadillac dealership or refer to online resources for any recalls or technical service bulletins that may be relevant to OBDII code B3801 and the Passenger Compartment Lamp Request Circuit.