AutoCodes – GMC – P0603 GMC

P0603 GMC 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 GMC 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 4,049

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 Mar 29, 2024

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0603 GMC 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 GMC - Control Module Long Term Memory Reset - AutoCodes.com — P0603 GMC Code - Control Module Long Term Memory Reset

What does this mean?

What are the Possible Causes of the DTC P0603 GMC?

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 GMC?

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 GMC 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 GMC code?

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

Need Help with the Code?

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

Information for Specific GMC Models

P0603 2014 GMC Sierra — Control Module Long Term Memory Reset
P0603 2015 GMC Sierra — Control Module Long Term Memory Reset
P0603 2016 GMC Sierra — Control Module Long Term Memory Reset
P0603 2017 GMC Sierra — Control Module Long Term Memory Reset
P0603 2018 GMC Sierra — Control Module Long Term Memory Reset

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 GMC Code

1. What are the common symptoms of OBDII code P0603 in a GMC vehicle?

- The common symptoms of OBDII code P0603 include engine stalling, rough idling, poor fuel efficiency, and possibly issues with starting the vehicle.

2. What does the OBDII code P0603 "Control Module Long Term Memory Reset" mean in a GMC vehicle?

- The code P0603 indicates that the Engine Control Module (ECM) has detected a loss of long-term memory or that the memory has been reset.

3. What are the possible causes of OBDII code P0603 in a GMC vehicle?

- The possible causes of code P0603 include a faulty ECM, a dead or disconnected battery, poor electrical connections, or even issues with the vehicle's software.

4. How can I diagnose OBDII code P0603 in my GMC vehicle?

- Diagnosing code P0603 typically involves checking the electrical connections to the ECM, inspecting the battery for proper voltage, and using a diagnostic scanner to reset the ECM and monitor its behavior.

5. Can I continue driving my GMC vehicle with OBDII code P0603 present?

- It is not recommended to drive your GMC vehicle with code P0603 present, as it can lead to more serious issues with the engine's performance and overall drivability.

6. How can I repair OBDII code P0603 in my GMC vehicle?

- Repairing code P0603 may involve resetting the ECM, checking and repairing any faulty electrical connections, ensuring the battery is in good condition, or replacing the ECM if necessary.

7. Is it possible to reset OBDII code P0603 in a GMC vehicle without professional help?

- While some simple troubleshooting steps can be taken, it is recommended to seek professional help to properly diagnose and repair OBDII code P0603 in a GMC vehicle.

8. Will disconnecting the battery reset OBDII code P0603 in a GMC vehicle?

- Disconnecting the battery may temporarily clear the code, but it is not a permanent solution. It is important to diagnose and address the underlying issue to prevent the code from reappearing.

9. How long does it take to repair OBDII code P0603 in a GMC vehicle?

- The time it takes to repair code P0603 can vary depending on the cause of the issue. Simple fixes like resetting the ECM or checking electrical connections may take less time, while more complex repairs could require more extensive work.

10. Can OBDII code P0603 in a GMC vehicle be triggered by a one-time issue?

- Yes, code P0603 can sometimes be triggered by a one-time issue such as a momentary loss of power. However, if the code reoccurs, it indicates a persistent problem that needs to be addressed.