P0422 obd2 code: Causes, Symptoms, Diagnose & Fixes

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How to fix P0422 obd2 code?
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Owning a vehicle can cost you much when it comes to maintenance – and you must have the know-how of issues that can be fixed without spending much. A vehicle’s self-diagnosing equipment, also known as OBD2 (On-Board Diagnostic II), essentially plays its part in detecting malfunctioning or problems in light to medium-duty vehicles. For instance, if there is an issue in speed, mileage, emissions, or other data, it illuminates a warning light. 

OBD code P0422; What is it and what does it indicate?

OBD code P0422; What is it and what does it indicate?However, OBD code P0422 indicates the main catalyst efficiency is below the threshold in bank 1 of the engine, which is one of the cylinders arranged in parallel to the crankshaft.

How to determine the efficiency of catalysts?

The PCM (powertrain control module) measures a vehicle’s catalyst efficiency by collecting temperature and exhaust data from downstream and upstream oxygen sensors. If you see, the results from the downstream and upstream sensors are too similar, the catalyst’s function is likely below the threshold. The PCM will report these signals as a P0422 error code on your OBD2.

P0422 Causes

The main indication for p0422 code error is lower efficiency. However, there can be various reasons that can contribute to the lower efficiency of the catalyst, for instance;

  • Faulty oxygen sensor
  • Broken coolant temperature sensor
  • Defected mass airflow sensor
  • Polluted engine oil
  • Front engine leak
  • Engine failure
  • Broken or loose wire connections

OBDII P0422 Error; Symptoms

To effectively understand the issue, you must understand common signs that indicate the error, which otherwise may be hard to notice without professional assistance. 

  • The first and foremost indication is that your dashboard lights may illuminate prominently.
  • You must not overlook a decrease in engine performance.
  • There are potential chances of a hissing noise coming out of the motor when you engage the throttle.
  • Increased emission from the tailpipe.

Diagnosing OBD P0422 Code Error

You can either go to a professional or get yourself some tools to assess OBD code errors at home. However, for further assistance and fixing, you will need to go to a mechanic. 

What tools do you need?

While diagnosing p0422 problems, it is best to start with turbo problems. The tools that you will need for the inspection are;

An OBD2 scanner is used to detect the codes. Running the scanner if you see any code, it is better to reset the codes and restart the vehicle. If there are no codes shown after the restart, it probably can be a false prompt. However, if you see the code P0422, start with; 

Vacuum Inspection

  • Leaks in the vacuum hoses
  • Jam or clogging in the hoses

Turbocharge Inspection

  • Install a vacuum gauge in the intake manifold.
  • Start the engine.
  • At idle, the vacuum must be between 1 to 1.5 atm. 
  • A vacuum less than 1 atm indicates a defective converter that does not allow boost. 
  • Look out for bent or resisting blades and oil in the turbocharger.

Electrical Components

  • If, after inspection, everything seems fine, you must go for solenoid and relevant circuits.
  • Test the control circuit by disconnecting the wiring harness from the bypass damper pressure regulator solenoid. 
  • Open or shorted solenoid indicates failure. Therefore, you must replace it to solve issues with no resistance. 
  • When the ignition is on, the solenoid supply circuit must have 12 volts. If it is missing when the ignition is on, you need to change or repair the wire from the PCM to the solenoid.
  • The pressure control solenoid pressure control valve supercharger is grounded. Solenoid valve ground circuit with a test bulb connected to the battery’s plus end Use the control solenoid. A defective circuit reveals no control light.

Mistakes To Avoid While Diagnosing OBD P0422 Error

There are a few minor things that must be considered while checking for the p0422 error code for enhanced accuracy. You probably do not want to end up diagnosing the wrong code. To solve the problem efficiently, it is important to get to the root cause. 

  • The most common misconception regarding code p0422 error is that an oxygen sensor is not a prime reason. You must check out oxygen sensors separately to make sure that it is not the problem triggering the p0422 code. 
  • Whether you are new to it or feel like you are a pro, it is essential to follow diagnosis protocols for OBD2. On the other hand, there are potential chances of failing to address the real issue. 

How To Fix p0422 Code Error

How To Fix p0422 Code Error

You do not have to panic when the lights pop up on your dashboard or not every time you need to go to a mechanic. We are listing a few fixes on how to fix the p0422 code that can help with the code p0422 issues. 

  • Repairing or fixing the catalytic converter
  • Replace damaged oxygen sensors
  • Install new wires for the electrical connectors
  • Fixing the engine leaks 
  • Fix the mass airflow sensor
  • Replace your broken manifold air pressure sensor
  • Replacing a fuel pressure regulator
  • New coolant temperature sensor

Finding the issues in-depth, you can conveniently fix these issues with minor adjustments on your own. However, you can always take professional help, if necessary. 

Tips for further avoiding p0422 obd2 error

Proper maintenance and care of your vehicle time and again surely save you from major issues that can cost much. If you want to prevent main catalyst efficiency below the threshold, here are some simple measures that you can take;

  • A hard drive once in a while is helpful in burning off the build-up in the catalyst converter. 
  • Regular clean-up of your engine can help in better performance.
  • Keep changing engine oils. 

Vehicles that usually face the P0422 issue?

Some vehicles the potentially face code p0422 OBD2 error, including;

  • Mazda 
  • Volkswagen 
  • GMC
  • Mercedes 
  • Volvo


How serious is OBD2 error code P0422?

If the P0422 code is detected at an early stage, major issues can be prevented. However, issues in main catalyst efficiency below the threshold can lead to the vehicle not starting. 

How can I tell if I have an OBD1 or OBD2 catalyst?

Vehicles before 1988 models used OBD1 to monitor performance functions. With increased emission malfunctioning factors, all the 1997 models require OBD2 systems. To identify if your vehicle has OBD1 or OBD2, check for the port. The OBD-II features a 16-pin port.

Does OBD2 cost more than OBD1?

Depending on the OBD system, updating to OBD2 is quick and easy including minimal additional hardware. Adding new software to an onboard system can be upgraded to your requirement.