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P0432 OBD-II Trouble Code: Main Catalyst Efficiency Below Threshold (Bank 2)

check engine light

P0432 code definition

The P0432 code indicates that the efficiency for the catalytic converter on engine bank 2 is below efficiency. It may also appear in conjunction with the P0434 code (heated catalyst temperature below threshold for bank 2), or with one or more oxygen sensor codes.

What the P0432 code means

The P0432 code means that your catalytic converter for bank 2 of your engine is performing below what it should be. Generally, this is a sign that the converter has failed, but the problem may be related to an oxygen sensor. The catalytic converter is responsible for burning harmful emissions in your exhaust, and if it is not working efficiently, then it will not do this. The car’s computer monitors converter operation and efficiency with oxygen sensors.

What causes the P0432 code?

The P0432 code may be caused by a number of problems, including the following:

  • A failed catalytic converter (note that there are multiple reasons failure, including excess fuel being dumped into the exhaust, premature failure, internal component melting and more)
  • A failed oxygen sensor
  • A leak in the exhaust system above the catalytic converter

What are the symptoms of the P0432 code?

A range of symptoms is possible with the P0432 code. These include:

  • No symptoms
  • Check Engine Light is on
  • Loss of power
  • Engine stalling
  • Engine hesitating on acceleration
  • Hissing noise on acceleration
  • No start

How does a mechanic diagnose the P0432 code?

Diagnosing the P0432 code will first require the mechanic to connect an OBD II scanner to the car’s computer. The codes will be read and then cleared. The car will then be test driven to see if the codes reset.

The next step will be to determine whether the catalytic converter has actually failed, or if there is another reason for the code to be set. If there is an oxygen sensor code stored too, then the O2 sensor will need to be replaced before the converter can be diagnosed.

It is also important for the mechanic to check for exhaust leaks in the manifold and other exhaust components ahead of the catalytic converter. Often, leaks in these areas can cause the computer to inaccurately set the P0432 code. If leaks are found, they will need to be repaired and then the system retested (to see if the code resets again), before the catalytic converter can be replaced.

Common mistakes when diagnosing the P0432 code

The most common issue with this code is replacing the catalytic converter without determining what caused it to fail in the first place. While internal melting is possible due to simple premature failure, it is more likely that there is an underlying problem responsible, which will in turn cause the new converter to fail prematurely as well.

How serious is the P0432 code?

The P0432 code may be serious, or it may not. It really depends on the nature of the failure. In all instances, you will not be able to pass your emissions test. In addition, it is possible that you’ll experience drivability problems up to and including a no start situation. Have your car diagnosed as soon as possible.

What repairs can fix the P0432 code?

The repairs needed to fix the P0432 code will depend on what has actually gone wrong with the car. They can include:

Additional comments for consideration regarding the P0432 code

An operational catalytic converter is vital for emissions control. However, bear in mind that the P0432 code may not indicate that the catalytic converter is bad. Even if it has failed, most are warrantied for up to 100,000 miles by the automaker.

Need help with a P0432 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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