Error code p0420 Toyota, Ford and other cars

We live in a world that is in step with the times. Computer technology as early as the end of the last century did not pass by automobile production. The first car with on-board diagnostics was introduced by Volkswagen back in 1968.

On-board diagnostics

Every driver who has a modern car knows about the on-board diagnostic system in the car, with which you can find the car's malfunctions. In a literal sense, the car itself determines where and what is its malfunction, and provides a certain diagnostic code to the device, by means of which the driver or master determines the malfunction and seeks repair methods.

Error p0420

A fairly common diagnostic error code. In the information space, and simply in everyday life from the owners of cars you can hear a lot of information, rumors and tips about this code. Let's consider what does it mean, what kind of malfunction can it talk about, what methods of solving this problem exist.

What does the error code p0420 mean?

You see, as you have turned on the control indicator on the dashboard. You go to the car service center or, possibly, scan the car and find out that the problem is represented by the error p0420. After displaying the codes, first make sure that p0420 is the only code. If not, it is necessary to diagnose other codes, because they can call the code p0420. The reason for this is that the converter is the end result of the diagnosis. In principle, if there is a problem with one of the sensors in the engine or exhaust, this can lead to a decrease or increase in the amount of fuel entering the engine.

So, we see the code, and if there are no other than p0420, it often means that the efficiency of your catalytic system is lower than it needs to be measured by your oxygen sensors. This means there was a problem with either a catalytic converter, or with oxygen sensors, or both. The purpose of the catalytic converter is the destruction of harmful contaminants created during the combustion cycle. Using fine platinum and gold mesh for exhaust gas filtration, the catalytic converter is able to reduce emissions from the exhaust pipe. The catalytic converter has two oxygen sensors. One oxygen sensor is located in front (upstream) of the catalytic converter, and the other oxygen sensor is located behind (downstream). If the front oxygen sensor is operating correctly, its readings should fluctuate when the car is at operating temperature and when working in a closed loop. If the lower oxygen sensor works correctly and there are no problems in the catalytic converter, its readings should remain stable. When oxygen sensors have readings that are similar to each other, this indicates that the catalytic converter does not work properly. . If the voltage of the rear oxygen sensor decreases and begins to oscillate like the front oxygen sensor, this means that the oxygen levels are too high, and the powertrain control module will display the error code p0420 .

What's causing p0420?

• Damaged muffler or leaks in it.

• Damaged exhaust manifold or leaks present.

• Damaged exhaust pipes.

• A misfire in the engine.

• Oil contamination in the catalytic converter.

• Defective catalytic converter (most common).

• Defective engine coolant temperature sensor.

• Defective front oxygen sensor.

• Defective rear oxygen sensor.

• Damaged oxygen sensor wiring.

• The oxygen sensor wiring is not connected correctly.

• Damaged oxygen sensor connectors.

• Fuel Injector Leakage.

• High fuel pressure.

• Use of an incorrect type of fuel (leaded).

How does the mechanic diagnose the code p0420?

• Uses the OBD-II scanner to retrieve trouble codes stored in the PCM.

• Considers the current data of the downstream (rear) oxygen sensor. Determines if the oxygen sensor is operating correctly.

• . Diagnose any other codes that can cause the DTC p0420 .

• If necessary, eliminates misfires, problems with ignition and problems with the fuel system.

• Inspect the rear oxygen sensor for damage and excessive wear.

• Checks for PCM updates if the catalytic converter is faulty. After replacing the catalytic converter, PCM updates are required.

Common errors in diagnosing the code p0420

The most common mistake is the replacement of oxygen sensors before the completion of the diagnostic process. If another component causes a fault code p0420, replacing the oxygen sensors will not solve the problem.

How serious is p0420?

The driver does not have to experience control problems if a fault code p0420 is present. In addition to the on-board indicator, the symptoms of this DTC may go unnoticed. However, if the car is operated with an error and this problem is not solved, other components may be seriously damaged. Since there are no control problems with p0420, this is not considered serious or dangerous for the driver. However, if the code is not eliminated in a timely manner, the catalytic converter may be seriously damaged. Since the catalytic converter is expensive to repair, it is very important that the fault code p0420 be diagnosed and repaired as soon as possible.

What repairs can the code p0420?

• Replace the muffler and repair leaks.

• Replace the exhaust manifold and repair leaks.

• Replace the exhaust pipe.

• Replace the catalytic converter (most common).

• Replace the engine coolant temperature sensor.

• Replace the front or rear oxygen sensor.

• Repair or replace damaged wiring with oxygen sensors.

• Repair or replace the oxygen sensor connectors.

• Replace or repair the fuel injectors that are leaking.

• Diagnose any repairs in case of any problems with missing the ignition.

• Diagnose and eliminate any other related fault codes that have been stored by the Power Management Module (PCM).

Cheating p0420 errors

Very often you can meet a glowing fault indicator after refueling your car with poor-quality fuel. The p0420 error on the Ford Focus is a fairly common thing, and this model is a frequent visitor to a car workshop with this code. The reason for the appearance is the problem with the catalyst described above, it is solved by searching for the reasons for the inefficient operation of the catalytic converter. There are options for the complete removal of the catalyst, because its high cost does not justify a replacement for a new one. But the removal does not solve the problem of error p0420 on "Ford". To make it disappear and the indicator does not bother you, you need to deceive the computer or the sensor (lambda probe 2). There is a mechanical, electronic and software way to shutdown. Mechanically, the sensor is inserted into the manifold with a spacer and a hole in it. The electronic method involves placing a resistor in the signal wiring, which will remove the error p0420 on your Ford. The software way is the firmware of the on-board computer system, is the most complicated way, since a competent specialist of this kind of activity is needed. These methods in most cases will help to avoid the error of p0420 on "Ford Focus 2" and "Ford Focus 3".

Also there are services that produce and install flame arresters instead of catalyst. For example, if we are talking about "Mazda 3" (error p0420 is often found on it), for her the correct way to eliminate this problem is the replacement of the catalytic converter with a flame arrester. Another way is to install a catalyst emulator. One of the most popular is the Spider CE2, it is easily connected to the cable by a post-catalyst sensor, and the problem is solved. This method is very often used in the case of a p0420 error on the Toyota Corolla, because it is quite easy to get to the wires of the lambda probe. The use of the emulator does not work in all cases.

When the p0420 error on the "Suzuki" drivers prefer to knock out the catalytic converter and flash the brains of the car to the Euro-2 standard by the chip-tuning method. On some models of "Suzuki" the use of the emulator is useless, the error still appears and leads to all the ensuing consequences. The way of firmware of the software is also used, although it, as was mentioned above, is rather complicated.

We describe the popular method using the example of the error p0420 in "Subaru". For cars of this brand there is a special firmware for the control unit, where these errors are disabled and never appear again. This solves the problem with the indicator and the on-board system, but only if it is associated with the damage or wear of the oxygen sensors and the catalyst.

Additional comments for reviewing the code p0420

Problems with the ignition system, fuel system, air intake and ignition misfire can damage the catalytic converter if they are not eliminated quickly. These components are the most common cause of the fault code p0420. In some cars, due to this error, cruise control and stabilization system cease to work. In the CIS countries, problems with the catalyst arise due to the poor quality of our fuel, which is not designed for the ecological standards "Euro-3" or higher. Therefore, foreign cars, whose catalytic systems are produced for the use of high-quality fuel, fail. All the previously described problems with the catalyst appear, and it quickly wears out, respectively, showing us a diagnosis of a known error.

conclusions

If the bug prevents you, do not want to remove the catalytic converter, strive for the machine to comply with environmental standards, then you will have to repair and prevent it. Here are some useful tips:

1. Special tools, such as Catalytic Converter Cleaner, purify the catalyst, thus prolonging its service life.
2. Refuel only on proven gas stations and high-quality fuel. Otherwise, it will be necessary to replace the catalytic converter, and its cost is quite high.

Cheaper alternatives to prevent the appearance of the described error are the installation of emulators and reprogramming the system. These options will not worsen the performance of the car, and in some cases even improve it.