AutoCodes – Generic – B3187

B3187 Code - Left Rear Window Down Switch Circuit Low

Quick Answer

This Diagnostic Trouble Code (DTC) is generated by a passenger door window switch or a passenger door window switch circuit. Common causes include Faulty Left Rear Window Switch, Left Rear Window Switch harness is open or shorted, Left Rear Window 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: B3187 indicates Left Rear Window Down Switch Circuit Low.
Common causes: Common causes include Faulty Left Rear Window Switch, Left Rear Window Switch harness is open or shorted, Left Rear Window 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 515

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 04, 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 B3187 Description

This Diagnostic Trouble Code (DTC) is generated by a passenger door window switch or a passenger door window switch circuit. Each passenger door window switch is mounted to the trim panel of the appropriate passenger door. The circuits and contacts of each passenger door window switch receive battery voltage and ground from the corresponding door module, i.e. Front Passenger Door Module (PDM), Left Rear Door Module (LRDM), or Right Rear Door Module (RRDM). When a passenger door window switch is operated, the switch contacts close and the associated door module interprets the flow of voltage as a specific request to move the window up or down. If conditions are correct for window operation to occur, the door module then powers the associated window motor and circuits to move the window.

OBDII Code B3187 - Left Rear Window Down Switch Circuit Low - AutoCodes.com — B3187 Code - Left Rear Window Down Switch Circuit Low

What does this mean?

What are the Possible Causes of the DTC B3187?

Faulty Left Rear Window Switch
Left Rear Window Switch harness is open or shorted
Left Rear Window Switch circuit poor electrical connection
Faulty Left Rear Door Module (LRDM)

How to Fix the DTC B3187?

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 B3187 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 B3187 code?

Need more information on how to fix the B3187 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B3187 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B3187 Buick — Left Rear Window Down Switch Circuit Low
B3187 Cadillac — Left Rear Window Down Switch Circuit Low
B3187 Chevrolet — Left Rear Window Down Switch Circuit Low
B3187 GMC — Left Rear Window Down Switch Circuit Low

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 B3187 Code

1. What are the common symptoms of OBDII code B3187 - Left Rear Window Down Switch Circuit Low?

The common symptoms include the left rear window being unable to roll down, a malfunctioning window switch, or the window getting stuck in a partially open position.

2. What causes the OBDII code B3187 to trigger?

The code B3187 is triggered when the powertrain control module (PCM) detects a low voltage condition in the left rear window down switch circuit.

3. How can I diagnose the cause of OBDII code B3187?

Diagnosing the code involves checking the wiring and connections related to the left rear window switch, testing the switch itself, and verifying the voltage levels in the circuit.

4. Can a faulty window switch cause the OBDII code B3187?

Yes, a faulty left rear window switch can be a common cause of the B3187 code as it may not be sending the correct voltage signals to the PCM.

5. What are some repair tips for resolving OBDII code B3187?

Inspect the wiring for any damage or loose connections, test the window switch for proper functionality, and ensure that the circuit is supplying the correct voltage levels to the PCM.

6. Is it safe to continue driving with OBDII code B3187 present?

It is generally safe to drive with this code, but it is recommended to address the issue promptly to avoid potential inconvenience or safety concerns related to the left rear window operation.

7. Can resetting the OBDII system clear the B3187 code?

Resetting the system may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to reappear once the problem is detected again.

8. Can moisture or water damage cause the B3187 code?

Yes, moisture or water damage can potentially affect the electrical components of the left rear window switch circuit and lead to the triggering of the B3187 code.

9. Are there any common recalls related to OBDII code B3187?

Recalls related to this specific code may vary depending on the vehicle make and model, so it is advisable to check with the manufacturer or authorized service centers for any relevant information.

10. How much does it typically cost to repair OBDII code B3187?

The repair costs for this code can vary depending on the specific cause of the issue, but it may involve expenses related to diagnosing the problem, replacing components, and labor charges, which could range from moderate to high.