Technical Description of OBD-II Trouble Code
Error in Internal Control Module Keep Alive Memory (KAM)
What does that signify?
This code is a generic powertrain code that applies to all makes and models of vehicles (1996-newer). However, the specific repair steps may vary slightly depending on the model.
The keep alive memory refers to the memory stored in the powertrain control module (PCM) regarding drive cycles. This memory constantly changes based on driving inputs and sensor inputs. When the battery is disconnected, this memory is erased and the computer enters a “dumb” mode, relying on built-in parameters rather than learned values based on driving inputs, habits, and sensor readings.
This is different from “limp” mode because the PCM is not detecting a fault. The PCM memory has not adapted to the required engine parameters. It does not refer to the hard-programmed values, but rather the ever-changing values that contribute to fuel economy, smooth running, easier starts, etc. This data is an adaptive formula used by the PCM to enhance engine performance, fuel trims, shift fuel, etc.
Other trouble codes related to internal control module errors include:
Photo of a PCM with the cover removed:
Symptoms
Symptoms of a P0603 DTC include illumination of the malfunction indicator lamp (MIL), along with other possible symptoms such as engine stall, various warning lights on the dashboard, module communication codes, and no start conditions.
Causes
Possible causes may include:
Possible Solutions
Isolating this problem can be quite challenging. Based on my experience, it could be either a wire issue or a PCM issue. It is possible that interference from a component has caused damage to the PCM.
Inspect the battery cables. It could be as simple as a highly corroded terminal or a loose connection. Also, check all grounds, fuse box, and PCM connections.
Check the charging system. Run the car with the alternator disconnected to see if there is any interference coming from the alternator. Does the code reappear when the alternator is disconnected?
Inspect wire harnesses that are in close proximity to the ignition system. Interference from these components may be affecting the circuit. Also, check the spark plug wires and coil for cracks or any areas where ignition voltage may be leaking.
Using a voltmeter, locate the power supply circuits to the PCM. Monitor the voltages while wiggling, bending, and shaking the harness around the engine and fuse boxes.
In many vehicles, the PCM is located in a secluded spot, which increases the chances of water getting into the PCM case and potential vibration transfer. If no faults are found, there may be an issue with the PCM itself.
Finally, if your vehicle has an aftermarket chip or program installed, it may be causing the issue. Additionally, manufacturers frequently update the available software for your computer, so the code may be resolved with a reflash.
