P0603 is a diagnostic trouble code (DTC) that pops up when there’s an issue with the Internal Control Module Keep Alive Memory (KAM) system, which stores the drive cycle information of a vehicle.
From what it means to how you can fix the underlying issue, here’s everything you need to know about this engine code.
What Does Code P0603 Mean?
The P0603 code stands for “Internal Control Module Keep Alive Memory (KAM) Error.” It can be a malfunction in either the wiring or the powertrain control module (PCM), or maybe even both.
The KAM in a vehicle module requires a direct battery connection that never goes dark unless the battery is dead or disconnected. Obviously, the wire that feeds the KAM is suspect if this code is stored, but if the wire is in good shape and there are no pin fit issues, the problem may be in the module that has stored the code.
The PCM is the internal computer that controls the engine’s fuel and ignition systems as well as all the emission controls and the transmission. Vehicles with a separate transmission control module (TCM) or a manual transmission have an ECM rather than a PCM since the module only controls the engine instead of both the engine AND transmission.
Using adaptive learning algorithms, modules track your driving habits and gradually use the data they have stored as the standard optimal settings of your vehicle.
This information is stored as the Keep Alive Memory (KAM) in the PCM, purely based on the two major driving and sensor inputs. Intentionally disconnecting your battery or losing the KAM power feed to the module means erasing this memory. Multiple potential factors at play can stop the PCM from retrieving these settings, which triggers the P0603 code.
As a generic powertrain code, P0603 can occur in different makes and models, particularly OBD-II vehicles such as Nissan, Infiniti, and Ford. It can have varying effects for every type, but it mostly affects older cars because they would have accumulated a larger volume of memory over time. It is important to keep in mind that all the following details in this guide can vary slightly for each vehicle.
What Causes Code P0603?
These are some of the possible causes that can trigger the P0603 code:
- Battery terminal issues
- Keep Alive Power (KAPWR) circuit problems
- Wiring or grounding issues
- Faulty charging or ignition system
- Internal PCM defects
Battery Terminal Issues
The simplest answer is that the code has something to do with the battery terminal, which needs to be maintained on all vehicles due to the corrosive/oxidative tendencies of the battery itself related to the electrolyte and the electrolysis of the metal terminals.
There might be some battery terminal corrosion or other loose connections that are causing the ground to short out. You can also check if the battery has enough charge to supply power to your vehicle.
Keep Alive Power (KAPWR) Circuit Problems
With the P0603 code, it mainly comes down to the Keep Alive Power (KAPWR) circuit. Possible culprits include issues with the wire routing, open wiring, or a blown fuse.
Wiring or Grounding Issues
Other than the KAPWR circuit, there might be something related to the wiring or grounding that is causing problems. These poor connections contribute to some unusual system behavior.
Faulty Charging or Ignition System
A malfunctioning charging or ignition system causes great interference to the voltage. There is likely an issue with the alternator, voltage regulator, or other wiring.
Internal PCM Defects
Perhaps the issue is much bigger than expected and lies within the PCM itself. There might be water intrusion, program errors, or insufficient power that is triggering the code.
What Are the Symptoms of Code P0603?
When you encounter the P0603 code, it’s typically accompanied by unusual behavior in your engine. Look out for symptoms such as:
- Malfunction indicator lamp (MIL) and other warning signals
- Rough starts and stalls
- Fuel and combustion issues
- Engine performance problems
- Poor transmission and emissions
Malfunction Indicator Lamp (MIL) and Other Warning Signals
Similar to other trouble codes, an illuminated malfunction indicator lamp (MIL) or check engine light serves as a warning for this code. There might also be some other warning lights or module communication errors that come into play.
Rough Starts and Stalls
Starting and stalling issues can be attributed to other codes, too, but you can never be too sure. If your engine is experiencing these problems, there’s a good chance that the P0603 code might be present. As the throttle body gathers sludge and the adaptive learning is applied to overcome that, if the KAM is lost, the ECM/PCM will default to its original settings and can cause the engine to stall. Other adaptive learning values will cause other issues as well.
Fuel and Combustion Issues
Dealing with a vehicle that is running out of fuel or has a misfiring engine can be challenging. These issues are not only indicators of the P0603 code but can also cause potential damage to your vehicle.
Engine Performance Problems
The P0603 code can affect your vehicle's smooth performance and drivability. Symptoms include rough idling, acceleration, and a difficult shifting process.
Poor Transmission and Emissions
Bad transmission shifts are just one of the many consequences of the P0603 code. On top of that, it might also result in failed emissions tests due to its strain on the engine’s performance.
How to Diagnose Code P0603
Careful attention to detail is necessary when you’re trying to investigate this code. Here are some steps you can take:
- Check for trouble codes
- Inspect the battery cables
- Check the charging system
- Inspect wire harnesses
- Check the PCM
Check for Trouble Codes
First things first. Pull out your OBD-II scanner and confirm the P0603 code. While you’re at it, look for the presence of other diagnostic trouble codes, which could further help pinpoint the main issue.
Inspect the Battery Cables
Take a look at all the cables connected to your battery. Inspect for signs of damage, corrosion, or loose connections.
Check the Charging System
Examine the charging system thoroughly to assess any form of damage. This insufficiency leads to low voltage, which greatly affects the internal components of your vehicle.
Inspect Wire Harnesses
Your next option is to observe the wire harnesses. Keep an eye out for anything suspicious with the wires connected to the fuse box.
Check the PCM
Inspect the PCM for possible water or moisture exposure. There might also be some faulty wiring around the area.
How to Fix Code P0603
Once you’ve determined the issue and fully charged your battery, you can finally fix the P0603 code. Here’s everything you can do to solve this issue:
- Repair or replace faulty wiring
- Replace alternator and battery
- Replace all defective components
- Reflash the PCM
- Review the system
Repair or Replace Faulty Wiring
Get the proper replacements for all the damaged wires and connectors that need fixing. Once you do, ensure that they are properly connected to prevent issues in the future.
Replace Alternator and Battery
The alternator and battery are two crucial components that require immediate solutions if they were to fail.
Replace All Defective Components
Whether they are separate parts in the control modules, battery grounds, or even the PCM itself, make sure that you replace them immediately to restore your vehicle to optimal operation.
Reflash the PCM
On the off-chance that your vehicle is running fine without issues but is still flashing the code, reflash the PCM to clear it completely.
Other Codes Related to P0603
You must keep an eye out for other diagnostic trouble codes while you’re solving the P0603 code. The other types of codes you need to look out for include:
P0601
This code refers to an issue with PCM’s memory checksum, which validates the data coming in. It appears when the PCM is unable to read the checksum, pointing to a larger problem within the internal memory of your vehicle.
P0602
This is one of the most common and generic diagnostic trouble codes. It focuses more on internal programming, where an error pops up in one of the individual control modules. It is a more general code, which is why you need to determine other codes to solve the error.
P0604
While the P0603 code refers to the KAM, this one involves the RAM (random access memory), which helps the PCM access your usual engine data when requested. As opposed to the P0603 code’s focus on the internal control module, this one deals more with live operations and data processing.
P0605
This code deals with an issue regarding the read-only memory (ROM), a memory bank that stores critical permanent programming for vehicle operation. This includes ignition timing and fuel injection, among others.
FAQ
Is it safe to drive with code P0603?
Technically, it is safe to drive with Code P0603. It is relatively not as major as other internal system issues so you shouldn’t have a problem using it. However, the safety and condition of your vehicle must be your top priority.