Description of DTC code P0492

The AIR system (Air Injection System) provides fresh air to the exhaust system during cold weather starts. It also feeds oxygen and exhaust gases. This ensures more complete combustion of hydrocarbons. It is worth mentioning that after one minute this system shuts off automatically.

When the P0492 OBDII fault code is set, it is because the Powertrain Control Module (PCM) has found a fault in the AIR system. This is due to the secondary air flow of bank 2 being excessively below the limit set by the manufacturer.

Symptoms of fault code P0492

  • Check Engine light illuminated.
  • The engine may stall at idle.
  • Stalling during acceleration.

Causes of OBD2 P0492

The causes for which the DTC P0492 OBD2 is set are:

  • The check valve may be defective.
  • The relay may be faulty.
  • The injection pump blower may be malfunctioning.
  • The Secondary Air Pressure Sensor may be faulty.
  • Secondary air injection ports may be clogged.
  • Possible vacuum leak.

Possible solutions of the DTC code P0492

To troubleshoot the faults caused by the P0492 OBDII diagnostic code you should consider the following:

  • Inspect the injection pump. Remove the pressure hose and start the engine. Air should be pumping through the end of the disconnected hose. If not, disconnect the connector from the pump wiring harness and proceed to apply 12 volts to the pump using jumper wires. If the pump is functioning properly, use a multimeter to verify that 12 volts are present at the harness connector. If 12 volts are not present, inspect the fuses and relay. Replace any components that have problems.
  • If applying 12 volts to the pump does not work, the pump should be replaced.
  • Disconnect the pressure hose from the valve. Check if air comes out of the hose once you start the engine. If after one minute the valve closes and the airflow stops, the valve is working properly. But if the valve remains open, it is in bad condition. If the valve has closed, the problem is in the vacuum switch.
  • With a vacuum pump, start the engine with the pump on. If the valve is open, you should release the vacuum, but if the valve does not open or close, you should replace the valve.
  • Check the vacuum line from the check valve to the switch. If you find cracks or any other damage in the hose, you should replace the hose.
  • Replace the control switch.

Codes related to P0492

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