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How to Fix P0600 Code: What You Need to Know!

How to Fix P0600 Code: What You Need to Know!

You notice that your check engine light is illuminating, or you are having difficulty starting your car, you check your system for any stored OBD2 trouble code and you find a P0600 code. You might ask, what does it mean and how to fix P0600 code? If you find the trouble code P0600 or Serial Communication Link Malfunction stored in your system, it means that your car’s Engine Control Unit has lost the connection with one or more of its controllers or control modules. This problem can usually be fixed. How to fix P0600 code includes:

Auto Repairs Are EXPENSIVE

  • Replacing the entire Engine Control Unit of your car.
  • Inspecting and fixing the low battery voltage causes.
  • Replacing or repairing the Engine Control Unit wiring harness.
  • Diagnosing and repairing poor electrical connections.
  • Replacing a faulty sensor.

Experts are not encouraging do-it-yourself repairs for the P0600 code. This is because the ECU is a very important system for any car, so it needs to be handled with great care when it comes to diagnosing it and repairing it. However, if you want to know more about how to fix P0600 code, read on!

How to Fix P0600 Code: What is a P0600 Code?

Before we go through the process on how to fix P0600 code, we need to understand what a P0600 trouble code is. The P0600 code is a diagnostic trouble code that refers to a malfunction in the engine control unit or ECU's communication link. You might see this code along with a number of other codes stored in your system.

The P0600 trouble code stands for Serial Communication Link Malfunction. This code means that the engine control unit has lost the connection with one or more of its many controllers or control modules multiple times. Depending on the type of vehicle you own, the code might be an indication of an internal failure of the ECU or the ECU’s inability to communicate over the data network.

The engine control unit, or powertrain control module or engine control module found on many vehicles control as many as 18 actuators. These actuators are being controlled through a controller network. This is made possible thanks to the Control Area Network which is a series of wiring harnesses connected from the ECU to the controllers.

When the trouble code P0600 has been set, the ECU will set off the Check Engine Light on your dashboard. When this happens, the ECU will then switch to failsafe mode. The failsafe mode is enabled by your car’s system to prevent further damage to your vehicle. It is there to protect your vehicle and this failsafe mode will continue to be in effect until the system has detected a normal operation or the cause has already been fixed.

The list of the main control modules that are operated by the car’s onboard computer or the ECU includes the anti-theft, the air conditioning system, the emission system, the fuel injection system, ABS brakes, sunroof and seat position, cruise control, body ride control, the ignition system, proximity alerts, power windows, traction control system, turbo charger, transmission shift points, variable camshaft timing, and many more.

The P0600 code information can vary depending on your car’s specific makes. For your guide, here are some of the trouble code information for the vehicles’ specific makes.

  • P0600 – NISSAN A/T – Control Serial Communication Link Malfunction
  • P0600 – HONDA – Serial Communication Link Malfunction
  • P0600 – HYUNDAI – Serial Communication Link Malfunction
  • P0600 – FORD – Loss of Serial Communication Link
  • P0600 – DODGE – Powertrain Control Module Fault
  • P0600 – KIA – CAN Communication Bus
  • P0600 – CHRYSLER – Powertrain Control Module Fault
  • P0600 – MERCEDES-BENZ – Loss of Serial Communication Link
  • P0600 – ACURA – Serial Communication Link Malfunction
  • P0600 – MITSUBISHI – Serial Communication Link
  • P0600 – VOLKSWAGEN – Serial Communication Link
  • P0600 – LINCOLN – Loss of Serial Communication Link
  • P0600 – MAZDA – Communication Line Error
  • P0600 – SUBARU – Serial Communication Link
  • P0600 – INFINITI A/T – Control Serial Communication Link Malfunction
  • P0600 – JEEP – Powertrain Control Module Fault
  • P0600 – VOLVO – Loss Of Serial Communication Link
  • P0600 – MERCURY – Loss of Serial Communication Link

How to Fix P0600 Code: What Causes P0600?

To determine how to fix P0600 code, you need to know what causes it. If you know what causes the problem, you will know the actions you need to take to have it fixed and get rid of the P0600 trouble code P0600. So what causes this trouble code to occur?


The diagnostic code configuration P0600 OBD II can be set because of the following problems:


  • Your car’s engine control unit is no longer capable of functioning properly or has failed completely.
  • You have a low battery voltage.
  • Some of the connectors might be corroded or loose, which can hinder a good connection. A bad cable or wiring can also cause the trouble code P0600 to be set.
  • There are issues in the ground circuit.
  • One of the cables or wirings of the Control Area Network or CAN might be faulty or damaged.
  • Data network issues.


Basically, poor connection or a failing ECU is the most common reason why the trouble code P0600 is set, leading you to get a hand on the methods on how to fix P0600 code. In many instances, the engine control unit functions as a ground to control these units and modules rather than sending power to them. This is why it is more common that the problem is caused by loose or corroded connectors compared to broken or damaged wires between the two devices, or a poor ground. Remember that the engine control unit and the activator modules require good ground in order for them to work properly.


You also need to bear in mind the engine control unit, together with the transmission control module, is responsible for controlling many of the motor functions of your car, including the fuel to air ratio, engine timing, tire pressure, automatic transmission, and many more. These functions need input from various sensors, and the data needs to be precise. This enables your car’s onboard computer to tweak their adjustments on the spot, according to what the car needs. So when one of your car’s sensors fails to function properly, or if there are some faults in the wiring or connections, your system will automatically set the P0600 code.


This is why it is very important that you will be able to diagnose this code immediately and have the problem corrected. You will never know how serious the problem is or will become if it has been ignored. It is for this reason that aside from knowing how to fix P0600 code, you also need to know its common symptoms.


The trouble code P0600 is often misdiagnosed since it usually gives off some deceptive symptoms. You need to remember that this code is an indication of a failed communication problem. Like when your car suffers an ignition system failure, it can result in a misfire. If your car is misfiring, a mechanic might start to check or diagnose your car’s ignition system rather than considering that there is a problem with the communication.


The problem can happen when the engine control unit is not doing its job, which is to control the ignition control module. Although it might seem like the cause is a faulty ignition system, the control of the system itself can be the cause of it. So depending on where the failure has took place, you may notice some symptoms and it includes:

  • Illuminating warning lights such as the check engine light, transmission malfunction indicator, or other warning lights. You might also see some other trouble codes aside from the code P0600 along with the illuminating check engine light.
  • A significant increase of your car’s fuel consumption.
  • Rough running, stalling, poor acceleration, and other engine performance problems.
  • Difficulty starting your car or car won’t start at all.
  • Car is stuck in limp mode or failsafe mode.
  • Shifting problems.

How to Fix P0600 Code: How Do You Get Rid of the P0600 Code?

How to fix P0600 code can be done in several ways, but basically, you will just have to fix whatever component or problem that caused it. How to fix P0600 code include:


  • Replacing the entire engine control unit, which is the worst possible scenario if your car’s ECU has failed to function completely.


  • If the problem is caused by a low battery voltage, you will have to have it checked and diagnose the problem. Then have it repaired. You can also correct this problem by having your faulty battery replaced.


  • If upon checking your wirings or connections and you found out that there are some loose or faulty electrical connections, then you have to correct the problem as soon as possible. If you have found that some wirings have corroded, you can replace them. To prevent the problem from occurring again, you can use a rust proofing treatment on your wirings.


  • Replacing the ECU wiring harness might be needed if you or the mechanic find some problem with it.


  • If the problem is caused by a sensor that is faulty or has failed completely, it will be vital to have it replaced immediately. Just make sure that when you replace a faulty sensor, you need to clear the codes after, and perform a test drive to ensure that the faulty sensor was really the cause of the issue and is not just one of the symptoms.

Like mentioned earlier, experts are not recommending that you do some do-it-yourself repairs when it comes to ECU problems. The experts say that the diagnosis and the methods on how to fix P0600 code should only be done by a professional that has a diagnostic computer. This is because when you try to unplug the ECU yourself or any related wiring and probe the terminals, you might end up spending thousands of dollars on repairs if you make even the slightest errors.

Many cars will require you to install a memory saver before you can disconnect the battery so you can keep the memory of your ECU. If the memory of the engine control unit should be lost because of lack of power, your car won’t start until you have it reprogrammed at the dealer. When probing a wire, it should be systematically with the use of a wiring diagram and pin values. This is because when you accidentally probe the wrong terminal, the ECU or any related module will be damaged or destroyed.

A diagnostic computer tool is needed to diagnose the P0600 code since this tool can show the pin values and the modules in operation and will alert you of any abnormalities. It is a great tool used for diagnosing computer-related issues or connections without risking any damage to any of your components.

If a mechanic uses this tool, you might be able to discover some other symptoms or other trouble codes other than the P0600 code that can help you find the faulty component that is causing the problem much faster. When you discover the cause of the problem, you will be able to check the connections for any faults like corroded or loose terminals.

A mechanic will usually follow these procedures on how to fix P0600 code.

  • Using a scan tool to check for any other codes present aside from the P0600 code.
  • Checking the freeze frame data for every code to determine what the car’s condition was when the P0600 was set.
  • All the codes will then be cleared and a test drive will be performed in order to duplicate the signs.
  • The mechanic will then do a visual inspection and look for any signs of damaged, loose, or worn parts.
  • The battery voltage will then be checked to make sure it is not the one causing the problem.
  • The ECU’s power continuity and ground circuits will be checked using a multimeter.
  • Then the ECU will then be tested based on its manufacturer testing procedure which can vary from car to car depending on its make and model.

How to fix P0600 might seem easy, just having to correct the problem that caused it, but fixing it requires the right skills and the right tools. It should be handled by a professional and it should be done immediately since this problem can result in erratic symptoms that can affect your car’s operation.