Fault code P0603 – internal control module keep alive memory error

Fault code P0603 is called “Internal Control Module Keep Alive Memory (KAM) Error” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.

Technical description and explained code P0603

OBD-II code P0603 is defined as “activity control module memory error”. It is set when the powertrain control module (PCM) cannot store drive cycle information and the vehicle is running with its default parameters.

Fault code P0603 – internal control module keep alive memory error

The activity retention memory is the memory that is stored in the powertrain control module (PCM) with respect to driving cycles. The entries in the memory constantly change depending on the control and sensor inputs.

If the battery is disconnected, this memory is erased and the computer goes into basic mode as it uses the built-in parameters to start the engine. Not derived values based on data and driving habits and what the engine sensors see.

That is, it’s not rigidly programmed values, but constantly changing values that help save fuel, run smoothly, and start the engine more easily. The computer learns how you drive and can adapt the car’s performance to your specific needs and normal conditions.

Basically, error P0603 means that there is a problem with the transmission control module (PCM) maintaining activity control (driving cycles).

Symptoms of vehicle malfunctions

The main signal that an error P0603 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.

It can also be warning signs such as:

  1. Check engine control lamp on the control panel will light up (the code will be recorded in the memory as a malfunction).
  2. The engine stops or starts badly.
  3. Decreased engine power.
  4. Increased fuel consumption.
  5. There may be no symptoms except for the stored fault code.

Error P0603 is not considered serious, but it can cause discomfort. Therefore, it is recommended to solve it, as well as other problems.

Factors that can cause this error code

The error code P0603 can mean that one or more of the following problems have occurred:

  • Corrosion of battery terminals or loose connections.
  • Faulty charging system.
  • Broken or short circuit in wiring harness.
  • Loose or damaged connectors.
  • Ignition system malfunction resulting in secondary ignition voltage.
  • Internal PCM programming error.

How to fix or reset OBD-2 code P0603

Some suggested steps for troubleshooting and fix the error code P0603:

  1. Read all stored data and error codes with an OBD-II scan tool. To find out when and under what circumstances error P0603 appeared.
  2. Clear the error codes from the computer memory and test-drive the vehicle to find out if the malfunction appears again.
  3. If the error code appears again, visually inspect the electrical wires and powertrain control module (PCM) connector.
  4. Measure battery voltage and compare it to the manufacturer’s specification.
  5. Check continuity of powertrain control module (PCM) power and ground circuits with multimeter.
  6. Try reprogramming the control module.
  7. Evaluate powertrain control module (PCM) operation following vehicle manufacturer’s procedure.
  8. Clear the error code from the computer memory again, and test drive the vehicle to see if the problem is resolved.

Diagnose and repair of problems

To correct code P0603, the most common solution is to replace and reprogram the PCM. Although, faulty wiring should also be considered as a cause of this error.

Perform a thorough visual inspection of all points where the wiring rests on the body. These points represent ground connections. You will often find loose connections or even ground straps that hang down after unrelated repairs have been made.

If bad ground connections have been found and repaired, remove all codes and re-scan the system to see if any codes return. In some cases it may be necessary to re-integrate or even reprogram some controllers after a communication failure.

If all ground connections are secure, perform a thorough visual inspection of all wiring on the vehicle. Note that this inspection may require the removal of the dashboard, seats, carpets, and even trim panels to gain access to all wiring harnesses.

If no wiring damage is found, but the P0603 code remains despite following the steps above. One option may be to replace the entire electrical harness. However, this does not guarantee that the problem will be solved because the problem may be related to the controller.

Typical problems with controllers include faulty drivers, memory failure, or other components for any number of reasons. For this reason, replacing the entire harness is not recommended. Until exhaustive diagnostic tests have been performed on all controllers, including the PCM.

Checking and reprogramming

If the PCM has recently been replaced, there is a good chance that it has been improperly programmed or not programmed at all. In addition, you cannot use a controller from another vehicle. Unless it has been reprogrammed specifically for the vehicle in question.

Aftermarket (high performance) firmware may not be recognized by other controllers, resulting in a stored P0603.

Improperly programmed or replaced controllers may be reprogrammed by the factory scan tool. If you can’t access such a scanner, most dealerships offer PCM programming for a nominal fee.

Some aftermarket PCM manufacturers offer preprogrammed controllers for certain models. Contact your auto parts supplier and get the vehicle identification number, mileage, and other pertinent data.

On which vehicles does this problem occur most frequently

Fault code P0603 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:

  • Audi
  • Citroen (Jumper)
  • Ford (Expedition, F-150, Focus, Mondeo)
  • Honda (Accord)
  • Infiniti (FX37, G35, G37, QX56)
  • Mitsubishi (Pajero)
  • Nissan (350Z, Altima, Frontier, Juke, Maxima, Murano, Note, Teana)
  • Peugeot (307, Boxer)
  • Volvo
  • LADA (Kalina)
  • VAZ (2110, 2112, 2114)
  • ZAZ (Sens)

Fault code P0603 can sometimes be found with other errors. The most common are the following: P0100, P0231, P0237, P0470, P0472, P0601, P0602, P0604, P0605, P1247, P1273, P1280, P1293, P1610, P1611, P1690, U1001.


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