What Is the P0603 Code?
Symptoms
Causes
Seriousness
Can I Still Drive?
Diagnose
Difficulty of Inspecting
Get Additional Help
To understand the P0603 code, you first need to understand how the powertrain control module (PCM) works in a car. The PCM is a computer that controls essential systems like the ignition, transmission, and elements of your engine like its timing and the fuel/air mixture. As you drive, the PCM learns the best way to set these elements for your specific area conditions, your driving habits, and the special individualities of your vehicle. It saves these things as settings in an area called the Keep Alive Memory. If the PCM somehow cannot retrieve these settings, then it will throw a P0603 code.
More About the P0603 Code
The most important thing to know about the P0603 code is that its impacts will be different for every car, depending on how many setting changes and tweaks the car has needed to make over time. This means that typically, older cars will be most heavily impacted, as they’re the ones that will be most likely to need more adjustments and changes while driving.
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What Are the Symptoms of a P0603 Code?
The symptoms of this code will vary depending on the car. You may have no issues aside from simply the check engine light coming on. All the way on the other side, you could notice that your engine doesn’t start very smoothly, that you require more fuel, that you’re experiencing issues with both idling and acceleration, that your shifting process is difficult, and even that your engine is misfiring. Regardless of what side of the spectrum you’re experiencing, however, it’s best to talk to an expert about it.
What Are Some Causes of a P0603 Code?
The P0603 code typically pops up due to an issue with the power or wiring process. The most common problem is a blown fuse; if a cigarette adapter shorts out, for example, it can blow a fuse, causing the Keep Alive Memory to be lost. It may also be that your PCM generally isn’t receiving enough power, leading to the KAM having a level of power too low to retrieve its settings. It can also be a problem with the KAM or battery ground shorting out. At worst, it may be that the KAM module has failed, requiring replacement.
How Serious Is the P0603 Code?
As with most other elements of the P0603 code, the seriousness can vary. With a brand-new car that doesn’t have much of a KAM change, the problem can be very light and not serious at all. With a much older car that stores a lot of information in its KAM, the problem can be very serious and have significant negative impacts.
Can I Still Drive with a P0603 Code?
Typically, you can still drive with this code for at least long enough to get to a local repair shop. Especially if this is the only problem that you’re dealing with, you shouldn’t have serious enough problems that you really need to look at the safety of your vehicle. However, you will experience a reduction in driving quality until you get this code looked at and you’re able to access the KAM module once again.
How Easy Is It to Diagnose a P0603 Code?
The diagnosis process can be surprisingly difficult. Defects can be fairly minor, and if charging the car battery doesn’t fix it, you may need to look into a variety of areas that could be causing this code. Additionally, in some cases, it may just be a misfire, and it’s hard to know when the code is a misfire and when you just haven’t found the problem. It’s best to leave the diagnosis of the P0603 code to an expert.
How Difficult Is It to Inspect a P0603 Code?
The inspection process is also typically fairly difficult. You need to have an eye for wiring and voltage, and it’s important that you know what a defective wiring section looks like, even if it’s not very obvious. This is one of the reasons why beginner DIYers probably shouldn’t try to tackle a P0603 code on their own.
Need Additional Help with Your P0603 Code?
Your P0603 code will very likely need help from an expert to accurately determine the problem. It can often be very difficult for a DIYer to determine what’s going on with a P0603 code, and deciding whether to replace the PCM can be more work than you know how to do.
This is where Kelley’s list of repair shops near you can come into play. If you’re looking for a good repair shop in your area where you can easily get help repairing this code, then the list of shops nearby is a great place to start.
You can also get some help with your DIY car repair decisions using the KBB database of OBD-II codes. Whether you’re looking for more information about codes your car is throwing, or you just want to learn more about the diagnostic system in your car, this database is a great starting point.
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