P0412 OBD Error Code: Problem & Solutions

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Is the car engine running rich? Is the car’s Check Engine Light On? Do you notice increased emission from the taillight? All these are indications towards problematic Air Ignition System and emission system. This results in storing of P0412 error in the Powertrain Control Module

The Secondary Air Injection System Switching Valve is a valve controlled by the vehicle’s computer, which also controls the air injection into the engine’s exhaust system. The OBD P0412 error code refers to a problem with the circuit of the Solenoid, and not on the operation of the valve itself.

The fresh air supply tube comes with a check-valve, which works by preventing exhaust gas from going back up in to the air injection pump. The PCM monitors the driver that activates the air injection pumps for faults. When the PCM commands the air injection pump relay on, the control circuit voltage would be pulled close to zero. When the relay is commanded by the PCM to be off, the control circuit would have battery voltage present. If the PCM notices an unexpected voltage, it will set the Error Code P0412 in the system.

What causes this problem with the Secondary Air Injection System Switching Valve A Circuit Malfunction?

• Too high air injection switching valve voltage, indicating open circuit
• Too low air injection switching valve voltage, indicating short circuit
• Open control circuit
• Open/short on battery feed circuit to solenoid
• Open/short on battery feed to relay control circuit

1. Air Injection Pump - Any fault in the air pump will cause increased emissions. Replace them now!
2. Air Control Valve Relay - Faulty control valve relay will affect the air control and emission system. Thus, replace it immediately.
3. Air Injection Check Valve - Faulty valve can cause particulate matter and moisture to enter the system, thus ruining the performance. Replace faulty check valve immediately.
4. Diagnostic Tools - You will require quality diagnostic tools to resolve this OBD issue. Buy factory grade tools from us!
5. Air Injection Solenoid - Check for faulty air injection solenoid and replace it immediately. Buy from us now!
6. Exhaust Manifold - P0412 can also be due to problems in the exhaust manifold. Replace it now!

Willing to know some common symptoms of OBD Code P0412? Your wish is our demand. Have a look at them below:

Common Symptoms

• Air injection system pump not turning on
• Engine running rich
• Increase in tailpipe emissions

We have listed out some ways which would help you to correct the occurrence of OBD Code P0412. They are mentioned here as follows:

• Air injection pump and power relay replacement
• Air injection switch valve replacement
• Air injection solenoid replacement
• Repairing the wiring to the air injection pump power relay connection

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If you want to easily diagnose this fault code, then all you have to do is to follow the steps which are mentioned below:

• Scan the OBD codes and documents and freeze frame the data in order to verify the problem.
• Clear the engine codes and retest the air injection system for proper operation. If the code returns, start with the diagnosis.
• Test the air injection switching valve for the controlling of air injection pump operation.
• Checks the resistance of the air injection pump and air injection switching valve.
• Checks the air injection pump for proper voltage between the pins of power and ground.
• Check for problem with the PCM and repair or replace accordingly.

Common Mistakes When Diagnosing the P0412 Code

Following are the common mistakes while diagnosing OBD code P0412 error.

• Not checking for proper battery voltage above 8 volts to the air injection pump before replacing the pump for no air pumping out of it.
• Not checking the air injection pump power relay for burnt wire connections before replacing a bad air injection pump or air switching valve.