P2431 OBD-II Trouble Code: Secondary Air Injection System Air Flow / Pressure Sensor Circuit Range / Performance Bank 1

Check Engine Light

P2431 code definition

Secondary Air Injection System Air Flow / Pressure Sensor Circuit Range / Performance Bank 1

What the P2431 code means

The secondary air injection system is used to add air into the exhaust to reduce vehicle emissions. When the the incorrect flow is detected, the electronic control unit (ECU) detects this fault and sets the P2431 code. This code causes the Check Engine Light to be illuminated on the dashboard.

With the Check Engine Light comes a failsafe mode. The failsafe mode is used to protect the vehicle from further damage and will remain until normal pressure is detected or the code is repaired.

What causes the P2431 code?

  • Secondary air injection pump failure
  • Poor electrical connection
  • Open or short in the wiring harness

What are the symptoms of the P2431 code?

How does a mechanic diagnose the P2431 code?

  1. A mechanic will begin by hooking up a scan tool to the vehicle's DLC port to check for any codes stored in the ECU, including history or pending codes.

  2. Next, all the codes will be noted and then cleared

  3. The technician will now take the vehicle on a test drive to attempt to duplicate the symptoms present

  4. After the test drive has been completed, a visual inspection of the vehicle will be performed looking for any obvious signs of damage or failed parts

  5. Next, the scan tool will be used to access the vehicle’s datastream to check the secondary air pump operation (then voltage will then checked at the pump using a multimeter)

Common mistakes when diagnosing the P2431 code

Commonly, mistakes are made when steps are not completed or are not done in the proper order. This can cause easy-to-repair, obvious faults to be missed and more expensive repairs performed instead. When easy things are missed, it wastes time and money.

How serious is the P2431 code?

The P2431 code has a wide range of symptoms. In some cases, the driver may notice no adverse symptoms. On the other hand the vehicle may stall and run poorly. For vehicles that run poorly, they should not be driven until the vehicle can be repaired.

What repairs can fix the P2431 code?

  • Replacing the secondary air pump
  • Repairing or replacing a wiring harness
  • Resolving poor electrical connections

Additional comments for consideration regarding the P2431 code

A common point of failure of the secondary air pump is due to the moisture from the exhaust causing the pump to fail. When the pump fails, it can repeatedly blow the fuse. When this occurs, simply replacing the fuse will not fix the problem because the root cause is the pump itself.

An advanced level scan tool is extremely helpful when diagnosing the P2431 code. It is used by technicians to access the live datastream from the ECU which can tell important sensor information such as voltage and temperature .

Need help with a P2431 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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