Engine-CodesGMC – P1503 GMC

P1503 GMC Code - Theft Deterrent Fuel Enable Signal Not Correct

Quick Answer

The P1503 GMC diagnostic trouble code indicates that the Theft Deterrent Fuel Enable Signal is not correct. Common causes include Faulty wiring or connections in the anti-theft system, Malfunctioning theft deterrent module, Issue with the key or ignition system. 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
P1503 GMC indicates Theft Deterrent Fuel Enable Signal Not Correct.
Common causes
Common causes include Faulty wiring or connections in the anti-theft system, Malfunctioning theft deterrent module, Issue with the key or ignition system.
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.
Table of contents Created and updated by William Orellana on Sep 10, 2024
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Code P1503 GMC Description

The P1503 GMC diagnostic trouble code indicates that the Theft Deterrent Fuel Enable Signal is not correct. This signal is part of the vehicle's anti-theft system, which is designed to prevent unauthorized access to the fuel system and prevent the engine from starting if the correct signal is not received. When this code is triggered, it means that the signal being sent is not matching the expected values, leading to a potential issue with the anti-theft system.

OBDII Code P1503 GMC - Theft Deterrent Fuel Enable Signal Not Correct
P1503 GMC Code - Theft Deterrent Fuel Enable Signal Not Correct

Common Causes of P1503 GMC

  1. Faulty wiring or connections in the anti-theft system
  2. Malfunctioning theft deterrent module
  3. Issue with the key or ignition system
  4. Weak or dead battery in the key fob
  5. Faulty ignition switch

Symptoms of P1503 GMC

  1. Engine cranks but does not start
  2. Engine stalls unexpectedly
  3. Reduced power mode
  4. Security system alarm going off unexpectedly
  5. Check engine light illuminated

How to Fix P1503 GMC

  1. Perform a thorough inspection of the wiring and connections in the anti-theft system to check for any damage or loose connections.
  2. Test the theft deterrent module to ensure it is functioning correctly and replace if necessary.
  3. Check the key and ignition system for any issues and replace any faulty components.
  4. Replace the battery in the key fob if it is weak or dead.
  5. If the issue persists, consult a professional technician for further diagnostics and repair.

Cost to Fix P1503 GMC

The typical repair costs for resolving the P1503 GMC code can vary depending on the specific cause of the issue. On average, the cost of parts and labor for this repair can range from $200 to $500. However, it is essential to note that specific diagnosis time and labor rates at auto repair shops can vary based on factors such as location, vehicle make and model, and engine type. It is recommended to check local rates for a more accurate estimate.

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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 P1503 GMC Code

What does the OBDII code P1503 mean on a GMC vehicle?

The code P1503 indicates a problem with the theft deterrent system, specifically the fuel enable signal not being correct or received by the engine control module (ECM).

What are the common symptoms of code P1503 on a GMC?

Symptoms include the engine failing to start, the security light illuminating on the dashboard, and potentially limited or no fuel delivery to the engine.

What causes code P1503 on a GMC vehicle?

Common causes include a faulty theft deterrent module, damaged wiring or connectors in the fuel enable signal circuit, or a malfunctioning ECM.

How is the P1503 code diagnosed on a GMC?

Technicians typically check for related codes, inspect the theft deterrent module, test the fuel enable signal circuit for continuity, and verify proper communication between the module and ECM.

Can a dead battery trigger code P1503 on a GMC?

Yes, a dead or weak battery can sometimes disrupt the theft deterrent system, causing the P1503 code to appear.

How can code P1503 be fixed on a GMC vehicle?

Repairs may include replacing the theft deterrent module, repairing damaged wiring or connectors, or reprogramming the ECM to ensure proper communication.

Is it safe to drive a GMC vehicle with code P1503?

No, the P1503 code typically prevents the engine from starting, so the vehicle will likely be inoperable until the issue is resolved.

Will clearing the P1503 code fix the problem permanently?

Clearing the code may temporarily remove it, but the underlying issue must be addressed to prevent the code from returning and restore proper vehicle operation.

Can code P1503 be related to a faulty key or key fob on a GMC?

Yes, a malfunctioning or unprogrammed key or key fob can prevent the theft deterrent system from recognizing the correct fuel enable signal, triggering the P1503 code.

How much does it typically cost to repair code P1503 on a GMC?

Repair costs vary depending on the issue but can range from $100 to $600, including parts and labor, depending on whether the theft deterrent module, wiring, or ECM requires replacement.

Discuss the causes and fixes for P1503 GMC OBDII Code

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