DTC P0412: Secondary Air Injection Relay Control Circuit: Description
WARNING: This page is about a different car, the 2002 Pontiac Montana, 2002 Oldsmobile Silhouette, and 2002 Chevrolet Venture. However, it is still accessible from the selected car via links, so may be relevant.
Ignition voltage is supplied directly to the solenoid. The control module supplies the ground path to the solenoid control circuit via an internal solid state device called a driver. Each driver has a fault line which is monitored by the control module. When the control module commands the solenoid ON, the voltage on the control circuit should be low, near 0 volts. When the control module commands the solenoid OFF, the voltage on the control circuit should be high, near battery voltage. If the fault detection circuit senses a voltage other than what is expected, this Diagnostic Trouble Code (DTC) will set. The control module will monitor the control circuit for the following conditions:
- A short to ground.
- A short to voltage.
- An open circuit.
- An open solenoid.
- An internally shorted or excessively low resistance solenoid.