DTC P0418: Secondary Air Injection Pump Relay Control Circuit: Description

Ignition voltage is supplied directly to the AIR solenoid. Powertrain Control Module (PCM) supplies the ground path to the AIR solenoid control circuit via an internal solid state device called a driver. Each driver has a fault line which is monitored by the PCM. When PCM commands AIR solenoid on, voltage on the control circuit should be about zero volts. When PCM commands AIR solenoid off, voltage on the control circuit should be battery voltage. If fault detection circuit senses a voltage other than when is expected, Diagnostic Trouble Code (DTC) P0418 will set.