AutoCodes – GMC – P1003 2015 GMC Sierra

P1003 2015 GMC Sierra Code - Fuel Composition Signals Message Counter Incorrect

Quick Answer

Control modules connected to the serial data circuits monitor the communication during normal vehicle operation. Common causes include Faulty Fuel Composition Sensor, Fuel Composition Sensor harness is open or shorted, Fuel Composition Sensor 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: P1003 2015 GMC Sierra indicates Fuel Composition Signals Message Counter Incorrect.
Common causes: Common causes include Faulty Fuel Composition Sensor, Fuel Composition Sensor harness is open or shorted, Fuel Composition Sensor 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 179

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 Aug 18, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1003 2015 GMC Sierra Description

Control modules connected to the serial data circuits monitor the communication during normal vehicle operation. Operating information and commands are exchanged among the control modules. Each module on the serial data circuit maintains a transmit error counter and a receive error counter. The counter values increase with detected errors and decrease with error-free messages. The Diagnostic Trouble Code (DTC) will be set when the Fuel Composition Signals Message Counter Incorrect.

OBDII Code P1003 2015 GMC Sierra - Fuel Composition Signals Message Counter Incorrect - AutoCodes.com — P1003 2015 GMC Sierra Code - Fuel Composition Signals Message Counter Incorrect

What does this mean?

What are the Possible Causes of the DTC P1003 2015 GMC Sierra?

Faulty Fuel Composition Sensor
Fuel Composition Sensor harness is open or shorted
Fuel Composition Sensor circuit poor electrical connection

How to Fix the DTC P1003 2015 GMC Sierra?

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 P1003 2015 GMC Sierra 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 P1003 2015 GMC Sierra code?

Need more information on how to fix the P1003 2015 GMC Sierra code? Get Access to Factory Service Manuals

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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 P1003 2015 GMC Sierra Code

1. What does the OBDII code P1003 mean on a 2015 GMC Sierra?

The P1003 code indicates that the fuel composition sensor is detecting an issue with the signal message counter, meaning itâ€™s sending incorrect or invalid data.

2. What are the common symptoms of the P1003 code on a 2015 GMC Sierra?

Symptoms may include the check engine light turning on, poor fuel efficiency, rough idling, and reduced engine performance.

3. What causes the P1003 code to appear?

Common causes include a faulty fuel composition sensor, damaged wiring, loose electrical connections, or a malfunction in the engine control module (ECM).

4. Can the P1003 code affect drivability?

Yes, it can lead to drivability issues such as hesitation, rough acceleration, or poor fuel adaptation, especially if the vehicle uses flex-fuel.

5. How can I diagnose the P1003 code on my 2015 GMC Sierra?

Start by checking for damaged wiring or loose connections at the fuel composition sensor. Use a scan tool to monitor the fuel composition sensor signal and verify if itâ€™s functioning correctly.

6. Is the fuel composition sensor the only component that can trigger the P1003 code?

No, other issues like a malfunctioning ECM or problems in the wiring harness can also lead to this code.

7. How do I fix the P1003 code on my GMC Sierra?

Repairs may include replacing the fuel composition sensor, fixing damaged wiring, securing loose connections, or reprogramming the ECM if necessary.

8. Can I continue driving with a P1003 code on my 2015 GMC Sierra?

While the vehicle may still be drivable, ignoring the code can lead to further engine performance issues and potential damage over time.

9. How much does it cost to fix the P1003 code?

Repair costs vary depending on the issue. Replacing a fuel composition sensor typically costs between $200-$400, while wiring repairs or ECM reprogramming may cost differently.

10. Can a faulty fuel composition sensor trigger other codes besides P1003?

Yes, a faulty sensor can trigger related codes such as P0178 or P0179, which indicate issues with fuel composition readings.