AutoCodes – Generic – B2503

B2503 Code - Right Lamp Low Beam Circuit Failure

Quick Answer

The Smart Junction Box (SJB) sends reference signals to the headlamp switch through circuits. Common causes include Faulty Right Lamp Low Beam, Right Lamp Low Beam harness is open or shorted, Right Lamp Low Beam 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: B2503 indicates Right Lamp Low Beam Circuit Failure.
Common causes: Common causes include Faulty Right Lamp Low Beam, Right Lamp Low Beam harness is open or shorted, Right Lamp Low Beam 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 14,532

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 Dec 16, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B2503 Description

The Smart Junction Box (SJB) sends reference signals to the headlamp switch through circuits. When the headlamp switch is placed in the HEADLAMPS ON position, the voltage signal is routed to ground through the circuit. If the SJB detects a fault with the headlamp switch inputs, the SJB turns the exterior lamps on by default. When the SJB detects the headlamp switch in the HEADLAMPS ON position and the multifunction switch in the LOW BEAM position, the SJB sends voltage through circuits to the low beam headlamps. When the SJB detects the headlamp switch in the HEADLAMPS ON position and the multifunction switch in the HIGH BEAM position, the SJB sends voltage through circuits to the high beam headlamps. The SJB sends a reference signal to the multifunction switch through circuits. When the multifunction switch is placed in the FLASH-TO-PASS or HIGH BEAM position, the voltage signal is routed to ground. When the SJB detects a request for the flash-to-pass, the SJB sends voltage to the high beam headlamps. The OBDII codes when the SJB detects a short to voltage from the Right (RH) low beam voltage supply circuit.

OBDII Code B2503 - Right Lamp Low Beam Circuit Failure - AutoCodes.com — B2503 Code - Right Lamp Low Beam Circuit Failure

What does this mean?

What are the Possible Causes of the DTC B2503?

Faulty Right Lamp Low Beam
Right Lamp Low Beam harness is open or shorted
Right Lamp Low Beam circuit poor electrical connection
Faulty Headlamp Switch
Faulty Smart Junction Box (SJB)

How to Fix the DTC B2503?

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 B2503 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 B2503 code?

Need more information on how to fix the B2503 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B2503 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B2503 Buick — Park Relay Shorted To Battery
B2503 Cadillac — Park Relay Shorted To Battery
B2503 Chevrolet — Park Relay Shorted To Battery
B2503 Chrysler — Left Power Sliding Door Latch Release Excessive Time
B2503 Dodge — Left Power Sliding Door Latch Release Excessive Time
B2503 Ford — Right Lamp Low Beam Circuit Failure
B2503 GMC — Park Relay Shorted To Battery
B2503 Lexus — Short In Roof Drive Motor Left Circuit
B2503 Lincoln — Right Lamp Low Beam Circuit Failure
B2503 Mercury — Right Lamp Low Beam Circuit Failure
B2503 RAM — Left Power Sliding Door Latch Release Excessive Time

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 B2503 Code

1. What are common symptoms of OBDII code B2503 (Right Lamp Low Beam Circuit Failure)?

- Common symptoms include the low beam light on the right side not functioning properly or not working at all.

2. What are possible causes of OBDII code B2503?

- Possible causes include a faulty low beam bulb, a damaged wiring harness, a defective headlight control module, or a problem with the vehicle's electrical system.

3. How can I diagnose OBDII code B2503?

- You can start by visually inspecting the right low beam bulb, checking the wiring connections, and using a multimeter to test for continuity in the circuit.

4. Can I repair OBDII code B2503 on my own?

- Depending on the cause, you may be able to repair the issue on your own by replacing the faulty bulb, repairing damaged wiring, or replacing a malfunctioning headlight control module.

5. Is it safe to drive with OBDII code B2503 illuminated?

- It is not safe to drive with a malfunctioning low beam light as it can reduce visibility, especially at night or in adverse weather conditions.

6. How much does it typically cost to repair OBDII code B2503?

- The cost of repairing OBDII code B2503 can vary depending on the cause of the issue, but it may range from a simple bulb replacement to more extensive repairs involving wiring or module replacement.

7. Can OBDII code B2503 affect other vehicle systems?

- While OBDII code B2503 specifically relates to the right low beam circuit, it can indirectly affect other systems by impacting overall visibility and safety while driving.

8. How often does OBDII code B2503 occur in vehicles?

- OBDII code B2503 is a relatively common issue in vehicles, particularly in older vehicles or those that have experienced electrical problems.

9. Are there any preventive measures to avoid OBDII code B2503?

- Regularly checking and maintaining your vehicle's lighting system, replacing bulbs promptly, and addressing any electrical issues promptly can help prevent OBDII code B2503 from occurring.

10. Can weather conditions affect the likelihood of OBDII code B2503 occurring?

- Yes, extreme weather conditions like heavy rain, snow, or ice can potentially contribute to the failure of the right lamp low beam circuit, triggering OBDII code B2503.