AutoCodes – GMC – P1003 2016 GMC Sierra

P1003 2016 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 2016 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 194

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 2016 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 2016 GMC Sierra - Fuel Composition Signals Message Counter Incorrect - AutoCodes.com — P1003 2016 GMC Sierra Code - Fuel Composition Signals Message Counter Incorrect

What does this mean?

What are the Possible Causes of the DTC P1003 2016 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 2016 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 2016 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 2016 GMC Sierra code?

Need more information on how to fix the P1003 2016 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

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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 2016 GMC Sierra Code

1. What does the OBDII code P1003 mean on a 2016 GMC Sierra?

P1003 indicates an issue with the fuel composition signal message counter being incorrect, which means the engine control module (ECM) is receiving unexpected or invalid data related to fuel composition.

2. What are the common symptoms of code P1003 in a 2016 GMC Sierra?

Symptoms may include poor fuel efficiency, reduced engine performance, difficulty starting the engine, and in some cases, the check engine light turning on.

3. What causes the P1003 code to appear on a 2016 GMC Sierra?

Common causes include a faulty fuel composition sensor, wiring or connection issues in the sensor circuit, a malfunctioning ECM, or the use of contaminated or improper fuel.

4. Can driving with the P1003 code damage my 2016 GMC Sierra?

While the vehicle may still be drivable, prolonged operation with this code can lead to poor performance and potentially damage the engine or emissions system over time.

5. How is the P1003 code diagnosed on a 2016 GMC Sierra?

A technician will typically use a scan tool to read live data from the fuel composition sensor, inspect the wiring and connectors, and possibly test the sensorâ€™s output to confirm the root cause.

6. Can a bad fuel composition sensor trigger the P1003 code?

Yes, a faulty or malfunctioning fuel composition sensor is one of the most common reasons for the P1003 code.

7. What repairs are recommended for fixing the P1003 code on a 2016 GMC Sierra?

Repairs may include replacing the fuel composition sensor, repairing or replacing damaged wiring or connectors, or updating/reprogramming the ECM if necessary.

8. Can contaminated fuel cause the P1003 code in a 2016 GMC Sierra?

Yes, using contaminated or improper fuel can interfere with the fuel composition sensorâ€™s readings, potentially triggering the P1003 code.

9. How much does it cost to repair the P1003 code on a 2016 GMC Sierra?

The cost varies depending on the exact issue, but replacing the fuel composition sensor typically costs between $200 and $500, including parts and labor.

10. Can I fix the P1003 code on my 2016 GMC Sierra myself?

If you have experience with automotive diagnostics, you can inspect the wiring and replace the fuel composition sensor yourself. However, more complex issues like ECM reprogramming may require professional assistance.