AutoCodes – Cadillac – B2603 Cadillac

B2603 Cadillac Code - DRL Relay Control Circuit Shorted To Battery Positive Voltage

Quick Answer

The Daytime Running Lamps (DRL) Relay is controlled by the Body Control Module (BCM). Common causes include Faulty Daytime Running Lamps (DRL) Relay, Daytime Running Lamps (DRL) Relay harness is open or shorted, Daytime Running Lamps (DRL) 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: B2603 Cadillac indicates DRL Relay Control Circuit Shorted To Battery Positive Voltage.
Common causes: Common causes include Faulty Daytime Running Lamps (DRL) Relay, Daytime Running Lamps (DRL) Relay harness is open or shorted, Daytime Running Lamps (DRL) 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 614

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 Jan 07, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B2603 Cadillac Description

The Daytime Running Lamps (DRL) Relay is controlled by the Body Control Module (BCM). Ignition positive voltage is applied to the DRL relay coil. The BCM grounds the DRL relay control circuit in order to turn on the DRL relay. When the DRL relay control circuit becomes shorted to battery positive voltage, DTC B2603 is set.

OBDII Code B2603 Cadillac - DRL Relay Control Circuit Shorted To Battery Positive Voltage - AutoCodes.com — B2603 Cadillac Code - DRL Relay Control Circuit Shorted To Battery Positive Voltage

What does this mean?

What are the Possible Causes of the DTC B2603 Cadillac?

Faulty Daytime Running Lamps (DRL) Relay
Daytime Running Lamps (DRL) Relay harness is open or shorted
Daytime Running Lamps (DRL) Relay circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B2603 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 B2603 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.

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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 B2603 Cadillac Code

1. What are the common symptoms of OBDII code B2603 in a Cadillac related to the DRL Relay Control Circuit?

The common symptoms include malfunctioning daytime running lights (DRLs), flickering or dim lights, or DRLs not turning on at all.

2. What could cause the DRL Relay Control Circuit in a Cadillac to short to battery positive voltage?

Possible causes include damaged wiring or connectors, a faulty DRL relay, a short circuit in the wiring harness, or a malfunctioning body control module.

3. How can I diagnose the DRL Relay Control Circuit issue in my Cadillac?

Start by checking the wiring and connectors for any visible damage or corrosion. Test the DRL relay for proper operation and continuity. Use a multimeter to check for shorts in the wiring harness.

4. Can I still drive my Cadillac with the DRL Relay Control Circuit shorted to battery positive voltage?

It is not recommended to drive the vehicle with this issue, as it can affect the proper functioning of the DRLs, which are important for visibility and safety on the road.

5. How can I repair the DRL Relay Control Circuit shorted to battery positive voltage in my Cadillac?

Repair options may include repairing or replacing damaged wiring, replacing the DRL relay, addressing any short circuits in the wiring harness, or resetting the body control module.

6. Is it possible to reset the OBDII code B2603 Cadillac without fixing the underlying issue?

Resetting the code without addressing the root cause will only temporarily clear the warning light. The issue will likely reoccur until the underlying problem is fixed.

7. Will fixing the DRL Relay Control Circuit issue in my Cadillac improve overall vehicle performance?

Fixing the DRL Relay Control Circuit will restore proper operation of the DRLs and ensure proper electrical functioning, but it may not have a direct impact on overall vehicle performance.

8. Can extreme weather conditions contribute to the DRL Relay Control Circuit shorting in a Cadillac?

Yes, extreme weather conditions, especially exposure to moisture or corrosion, can contribute to wiring or connector damage, which may lead to the circuit shorting.

9. How long does it usually take to repair the DRL Relay Control Circuit issue in a Cadillac?

The repair time can vary depending on the extent of the damage and the specific cause of the issue. It could take anywhere from a few hours to a full day to complete the repair.

10. Are there any preventive measures I can take to avoid the DRL Relay Control Circuit shorting issue in my Cadillac?

Regularly inspecting the wiring and connectors for damage, keeping them clean and dry, and addressing any electrical issues promptly can help prevent the DRL Relay Control Circuit from shorting in the future.