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P0603: Internal Control Module Keep Alive Memory (KAM) Error

Wondering why the check engine light is on and what P0603 has to do with it?

In addition to controlling all of the electronics that operate your vehicle, your vehicle's engine control computer also stores information related to how you drive. As it “learns” the way you drive, the computer adjusts aspects of vehicle performance to meet your specific needs so you experience optimum vehicle performance. This memory storage component is called the “Keep Alive Memory” (KAM) system. Anytime you see a P0603 error, it means the engine control module is not effectively using the stored information and is instead operating on default parameters.

Keep in mind that this particular code is not uncommon, especially for diesel trucks. Frequently, the code appears when aftermarket engine products are installed in a vehicle. If you see this error, you may wonder “How do I fix trouble code P0603?” Here’s a quick overview of the problem and potential fixes.

What Does P0603 Mean?

It means the drive cycle storage information is not effectively being communicated with the engine control module. If the underlying cause is not identified and corrected, the vehicle will not run optimally. In some cases, the vehicle may continuously stall and not run at all.

What are Possible Symptoms of P0603?

If your vehicle is exhibiting the following symptoms, there’s a good chance it will return a P0603 error:

  • Rough idle
  • Check engine light
  • Intermittent engine stumble
  • Increased consumption of fuel
  • Engine stalling problems
  • Other illuminated warning lights

If you experience one or more of these problems, your vehicle may return a P0603 error code when you run diagnostics.

What are Common Causes of Code P0603

There are several potential reasons you may have an OBD-ii scanner error code P0603 problem, including:

  • Faulty wiring to the engine control module
  • Aftermarket tuning products
  • Damaged or faulty engine control module
  • Faulty ignition system wiring
  • Water damage to the engine control module

The steps you take to fix the problem depend on the underlying cause. If the issue is a result of aftermarket parts, you may not be able to resolve the issue unless the aftermarket parts are removed and the original parts restored.

How to Fix P0603

It can be difficult to diagnose P0603 KAM codes, so follow these steps to make the process easier:

  • Fully charge your battery so all measurements you take are accurate.
  • Inspect the battery cables for corrosion, damage or loose connections.
  • Make sure the wires going into the fuse box wiring harness are undamaged.
  • Located and inspect the engine control module and all wiring going to and from it.
  • Measure the voltage of the wires supplying the engine control module. Your service manual will give you wiring instructions and show you the correct voltage.
  • Inspect the area for any signs of water intrusion, which can affect the function of the engine control module.
  • Replace or repair any faulty wiring, even if the defects seem minor.
  • Inspect the engine control module carefully if you see no signs of faulty wiring around it.

If your vehicle runs fine and there are no detectable problems besides the code itself, have the engine control module reflashed to clear the code.

Other Codes Related to the P0603

In some cases, the P0603 code may not appear on its own. Other codes commonly associated with the engine control module include:

  • P0607: Control Module Performance error
  • P0605: Internal Control Module Read Memory (ROM) Failure
  • P0604: Internal Control Module Random Access Memory (RAM) Error
  • P0601: Internal Control Module Memory Check Sum Error
  • P0600: Serial Communication Error

If you encounter any of these codes in addition to the P0603 code, troubleshoot them each individually to rectify the problem.

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