The engine control computer of your vehicle not only controls the electronic components, but it also stores data about your driving style. The computer adjusts the vehicle’s performance as it ‘learns” your driving style. This component of information storage is known as the “Keep Alive Memory” (KAM). When you get a P0603 error code, this means that your engine control module does not use the stored information effectively and instead operates with default parameters.
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When a vehicle is built, the PCM has factory default settings programmed for that particular model. These defaults may not be optimal. The PCM will make adjustments to your vehicle based on the characteristics of your vehicle, road and weather conditions typical in your area and your driving habits. Your PCM does not have to make hundreds of small adjustments every time you drive. Instead, it stores the settings in “Live Memory”. Your PCM will generate the P0603 code if it cannot retrieve these settings even after multiple attempts.
Diesel trucks are a common place to find this code. This code is usually caused by modifications made to the engine.
The vehicle will not perform optimally unless the root cause of the problem is identified and corrected. The vehicle may not start or stall in some cases.
What are the Symptoms of Fault Code P0603?
- Engine fault light illuminated
- Instability
- Intermittent engine stuttering
- Automatic gear change delay
- Fuel consumption increases
- Problems with the engine stalling
- Additional fault lights are illuminated
The P0603 error is most likely present if you experience any of these problems.
What causes the P0603 Fault Code?
- The engine control module is not correctly wired
- Aftermarket tuning products
- Engine control module that is faulty or defective
- Faulty ignition system wiring
- Water intrusion into the engine control module
If the problem you are experiencing is caused by modifications made to the vehicle after purchase, you may not be able to resolve the fault without removing these parts and reinstalling the original parts.
How to Fix the P0603 Fault Code?
Follow these steps to simplify the diagnosis of P0603 KAM codes:
- Charge your battery fully to ensure accurate measurements.
- Battery cables should be checked for damage or corrosion.
- Make sure the cables that lead to the fusebox wiring harness are not damaged.
- Find and inspect the engine controller module and all cables that lead to it.
- Measure the voltage on the wires that supply the engine control module.
- Check the area thoroughly for signs of water, which could interfere with the operation of the engine control modules.
- Even if they appear to be minor, replace or repair cables that are faulty.
- You should carefully examine the motor control module if you don’t see any indications of faulty wiring.
- Clear the code if your vehicle runs properly, and there is no other apparent issue than the code. Then retest it.
Other Codes Related to P0603
Other codes commonly associated with the engine control module include:
- P0607: Control module Performance Fault
- P0605: Internal control module Read-Only Memory Fault
- P0604: Internal control module Random Access Memory Fault
- P0601 Internal Control Module Memory Checksum Error
- P0600: Serial Communication Error
Investigate each code separately if you see any other codes than the P0603.
