Engine-CodesGeneric – P0603

P0603 Code - Internal Control Module Keep Alive Memory Error

Quick Answer

The P0603 diagnostic trouble code (DTC) refers to an Internal Control Module Keep Alive Memory Error. Common causes include Low battery voltage or a weak alternator, Faulty PCM or electronic control unit (ECU), Wiring or connection issues between the PCM and the KAM. 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 indicates Internal Control Module Keep Alive Memory Error.
Common causes
Common causes include Low battery voltage or a weak alternator, Faulty PCM or electronic control unit (ECU), Wiring or connection issues between the PCM and the KAM.
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 06, 2024
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Code P0603 Description

The P0603 diagnostic trouble code (DTC) refers to an Internal Control Module Keep Alive Memory Error. This error occurs when the powertrain control module (PCM) is unable to retain certain learned information, such as idle air control settings, fuel trim values, and transmission shift points, when the vehicle is turned off. The PCM relies on the Keep Alive Memory (KAM) to store this vital information, and when the KAM is corrupted or lost, it can lead to various performance issues and malfunctions in the vehicle.

OBDII Code P0603 - Internal Control Module Keep Alive Memory Error
P0603 Code - Internal Control Module Keep Alive Memory Error

Common Causes of P0603

  1. Low battery voltage or a weak alternator.
  2. Faulty PCM or electronic control unit (ECU).
  3. Wiring or connection issues between the PCM and the KAM.
  4. Software or firmware corruption in the PCM.
  5. Exposure to extreme temperature conditions or moisture.

Symptoms of P0603

  1. Rough idling or stalling.
  2. Poor acceleration and decreased engine performance.
  3. Reduced fuel efficiency.
  4. Inconsistent transmission shifting.
  5. Check Engine Light (CEL) illuminated on the dashboard.

How to Fix P0603

  1. Begin by checking the battery voltage and alternator output to ensure they are within the manufacturer's specifications.
  2. Inspect the wiring and connections between the PCM and the KAM for any signs of damage or corrosion.
  3. Perform a software update or reflash on the PCM to correct any firmware corruption.
  4. If the issue persists, consider replacing the PCM or ECU with a new unit.
  5. Clear the DTC and reset the PCM to allow it to relearn the necessary data.

Cost to Fix P0603

The cost of repairing a P0603 error can vary depending on the specific cause of the issue and the labor rates in your area. Typically, the cost of parts for this repair can range from $200 to $600, with labor costs adding an additional $100 to $300. Keep in mind that diagnostic time and labor rates at auto repair shops can fluctuate, so it's recommended to obtain quotes from multiple sources to get an accurate estimate.

Tech Notes for P0603

Start by charging the vehicle's battery and clean the 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 Engine Control Module (ECM) / Powertrain Control Module (PCM)

When is the Code Detected?

Indicates the Engine Control Module (ECM) / Powertrain Control Module (PCM) has experienced an internal memory fault.

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Code P0603 Information for Specific Makes

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 Code

1. What are the common symptoms of OBDII code P0603 (Internal Control Module Keep Alive Memory Error)?

- Common symptoms include engine stalling, rough idling, issues with starting the vehicle, and the illumination of the Check Engine Light.

2. What are the possible causes of OBDII code P0603?

- The code P0603 can be caused by a faulty powertrain control module (PCM), a dead or weak battery, a software issue within the PCM, or wiring problems.

3. How can I diagnose OBDII code P0603?

- To diagnose the code P0603, a technician will use a diagnostic scanner to retrieve the specific error code and then perform further testing to identify the root cause, such as checking the battery voltage and inspecting the PCM connections.

4. Can I continue driving my vehicle with OBDII code P0603?

- It is not recommended to continue driving your vehicle with the code P0603, as it can lead to potential safety hazards and further damage to the vehicle's components. It's best to address the issue promptly.

5. How can I repair OBDII code P0603?

- Repairing OBDII code P0603 typically involves replacing the PCM if it is found to be faulty, ensuring the battery is in good condition, updating the PCM software if necessary, and checking and repairing any damaged wiring or connections.

6. Is it possible to reset OBDII code P0603 without fixing the underlying issue?

- While clearing the error code may temporarily turn off the Check Engine Light, the code is likely to reappear if the underlying issue is not addressed. It is important to fix the root cause of the problem to prevent further issues.

7. Can a DIY enthusiast repair OBDII code P0603 at home?

- Repairing OBDII code P0603 may require advanced diagnostic tools and technical knowledge, so it is recommended to seek assistance from a professional mechanic to properly diagnose and repair the issue.

8. How much does it cost to fix OBDII code P0603?

- The cost of repairing OBDII code P0603 can vary depending on the underlying cause of the issue, the cost of parts needed for repair, and the labor rates of the repair shop. It's best to get a quote from a mechanic.

9. Is OBDII code P0603 a common issue in certain vehicle makes and models?

- OBDII code P0603 can occur in various vehicle makes and models that utilize an OBDII system. However, it may be more prevalent in certain vehicles known for PCM or electrical system issues.

10. Can a bad PCM cause other OBDII codes to appear along with P0603?

- Yes, a faulty PCM can cause other OBDII codes to appear in addition to P0603, as the PCM plays a crucial role in the vehicle's operation and can impact various systems. It's important to address any related codes during diagnosis and repair.

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