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AutoCodes – GMC – P0603 2017 GMC Sierra

P0603 2017 GMC Sierra Code - Control Module Long Term Memory Reset

Quick Answer

This diagnostic applies to internal microprocessor integrity conditions within the Engine Control Module (ECM). Common causes include Low battery voltage, Reprogram Engine Control Module (ECM), Faulty Engine Control Module. 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
P0603 2017 GMC Sierra indicates Control Module Long Term Memory Reset.
Common causes
Common causes include Low battery voltage, Reprogram Engine Control Module (ECM), Faulty Engine Control Module.
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 297
How popular is this code, among other codes? Low
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Table of contents Created and updated by William Orellana on Mar 29, 2024
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Code P0603 2017 GMC Sierra Description

This diagnostic applies to internal microprocessor integrity conditions within the Engine Control Module (ECM). This diagnostic also addresses if the ECM is not programmed. The ECM monitors its ability to read and write to the memory. It also monitors a timing function. No external circuits are involved. The Diagnostic Trouble Code (DTC) will be set when the ECM detects an internal failure or incomplete programming for more than 10 s.
OBDII Code P0603 2017 GMC Sierra - Control Module Long Term Memory Reset - AutoCodes.com
P0603 2017 GMC Sierra Code - Control Module Long Term Memory Reset
What does this mean?

What are the Possible Causes of the DTC P0603 2017 GMC Sierra?

  • Low battery voltage
  • Reprogram Engine Control Module (ECM)
  • Faulty Engine Control Module
  • Engine Control Module harness is open or shorted
  • Engine Control Module circuit poor electrical connection

How to Fix the DTC P0603 2017 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 does this mean?

Code Tech Notes

Start by charging the vehicle's battery and clean terminal, once the battery is charged and the terminals are clean and secured, erase the code. If the code comes back ON, then you may have to reprogram or replace Powertrain Control Module (PCM).

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0603 2017 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 P0603 2017 GMC Sierra code?

Need more information on how to fix the P0603 2017 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0603 2017 GMC Sierra code diagnosed by a professional: Find a repair shop in your area

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 P0603 2017 GMC Sierra Code

1. What does the OBDII code P0603 mean on a 2017 GMC Sierra?

P0603 indicates an issue with the Control Module's Long Term Memory, meaning the module has experienced a reset or lost stored data.

2. What are the common symptoms of code P0603 in a 2017 GMC Sierra?

Symptoms may include an illuminated Check Engine Light, intermittent stalling, rough idling, or a decrease in fuel efficiency.

3. What causes the P0603 code to appear on a 2017 GMC Sierra?

Common causes include a weak or failing battery, loose or corroded battery connections, faulty powertrain control module (PCM), or improper aftermarket tuning.

4. Can a bad battery cause the P0603 code in my GMC Sierra?

Yes, a weak or failing battery that disrupts the voltage supply to the PCM can trigger this code.

5. How do I fix the P0603 code on my 2017 GMC Sierra?

Start by checking and cleaning the battery terminals, ensuring the battery is fully charged, and inspecting the wiring. If the problem persists, the PCM may need reprogramming or replacement.

6. Is it safe to drive my 2017 GMC Sierra with the P0603 code?

While the vehicle may still operate, driving with this code can lead to further issues like stalling or poor performance. It’s best to address the issue promptly.

7. Can aftermarket tuning cause the P0603 code in a GMC Sierra?

Yes, improper aftermarket tuning or modifications to the PCM can interfere with its memory and trigger this code.

8. How much does it cost to repair the P0603 code on a GMC Sierra?

Costs vary depending on the issue, but reprogramming the PCM typically ranges from $80 to $150, while PCM replacement can cost $500 or more, including labor.

9. Will disconnecting the battery clear the P0603 code on my 2017 GMC Sierra?

Disconnecting the battery may temporarily clear the code, but if the underlying issue persists, the code will return.

10. Do I need to replace the PCM to fix the P0603 code?

Not always. Start with simpler fixes like checking the battery and connections. Replace the PCM only if diagnostics confirm it’s faulty.

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