AutoCodes – Generic – B3873

B3873 Code - Front Washer Relay Circuit

Quick Answer

The windshield washer function is controlled by the Body Control Module (BCM). Common causes include Faulty Front Washer Relay, Front Washer Relay harness is open or shorted, Front Washer Relay 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: B3873 indicates Front Washer Relay Circuit.
Common causes: Common causes include Faulty Front Washer Relay, Front Washer Relay harness is open or shorted, Front Washer Relay 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 3,037

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 Jun 14, 2023

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code B3873 Description

The windshield washer function is controlled by the Body Control Module (BCM). When the washer switch is pressed, low reference is applied through the switch contacts and the signal circuit to the body control module indicating the wash request. The body control module then applies voltage through the control circuit to the coil side of the windshield washer pump relay energizing the relay. With the relay energized, battery voltage from the fuse is applied through the switch contacts of the relay and the control circuit to the windshield washer fluid pump.

OBDII Code B3873 - Front Washer Relay Circuit - AutoCodes.com — B3873 Code - Front Washer Relay Circuit

What does this mean?

What are the Possible Causes of the DTC B3873?

Faulty Front Washer Relay
Front Washer Relay harness is open or shorted
Front Washer Relay circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B3873?

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 does this mean?

Code Tech Notes

B3873:01 Front Washer Relay Circuit Short to Battery
B3873:02 Front Washer Relay Circuit Short to Ground
B3873:04 Front Washer Relay Circuit Open

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B3873 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 B3873 code?

Need more information on how to fix the B3873 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B3873 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B3873 Buick — Front Washer Relay Circuit
B3873 Cadillac — Front Washer Relay Circuit
B3873 Chevrolet — Front Washer Relay Circuit
B3873 GMC — Front Washer Relay Circuit

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 B3873 Code

1. What are the common symptoms of OBDII code B3873 (Front Washer Relay Circuit)?

- The common symptoms include the front windshield washer not spraying fluid when activated, and the washer pump not making any noise.

2. What are the possible causes of OBDII code B3873?

- The possible causes could be a faulty front washer relay, a malfunctioning washer pump, a damaged wiring harness, or a blown fuse related to the washer system.

3. How can I diagnose the Front Washer Relay Circuit issue related to code B3873?

- You can start by checking the fuse associated with the front washer system, inspecting the wiring for any visible damage, testing the front washer relay, and checking the washer pump for proper operation.

4. Is it safe to continue driving with OBDII code B3873 present?

- It is generally safe to drive with this code, but it is important to address the issue promptly to ensure proper functioning of the front washer system, especially in adverse weather conditions.

5. Can I repair OBDII code B3873 (Front Washer Relay Circuit) myself?

- If you have basic automotive repair skills and the necessary tools, you may be able to repair this issue yourself by troubleshooting the relay, pump, and wiring, or replacing any faulty components.

6. What are some tips for repairing OBDII code B3873 efficiently?

- Start by checking the simplest possible causes such as a blown fuse or loose connection before moving on to more complex components like the relay or pump. This can save time and effort in the repair process.

7. How much does it typically cost to repair OBDII code B3873 in a professional auto repair shop?

- The cost of repairing this code can vary depending on the specific cause of the issue, but it may range from $100 to $300 for parts and labor in a professional auto repair shop.

8. Are there any preventive maintenance tips to avoid OBDII code B3873 in the future?

- Regularly checking and maintaining the front washer system, including keeping the washer fluid reservoir filled and ensuring proper operation of the washer pump, can help prevent issues that trigger this code.

9. Will fixing OBDII code B3873 affect my vehicle's overall performance?

- Fixing this code will primarily restore the functionality of the front washer system and may not directly impact the overall performance of the vehicle, but it is still important for safety and convenience.

10. How urgent is it to address OBDII code B3873 once it appears in the vehicle's diagnostic system?

- While it is not an urgent issue that affects the drivability or safety of the vehicle, it is recommended to address this code in a timely manner to ensure the front washer system operates correctly when needed.