Circuit Description

WARNING: This page is about a different car, the 2002 Oldsmobile Intrigue and 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.

The control module activates the Secondary Air Injection (AIR) system by grounding both the pump relay and the vacuum control solenoid control circuits. This energizes the pump and the vacuum control solenoid. Vacuum is then applied, opening the shut-off valves. The pump then forces filtered fresh air into the exhaust stream in order to accelerate catalyst operation. The control module will run up to three diagnostic tests using the pre-catalyst Heated Oxygen Sensor (HO2S) voltage and short term Fuel Trim (FT) to diagnose the system. The system can be diagnosed during normal secondary air injection operation or the control module can activate the system specifically for diagnostic purposes. If the system is operating properly, the HO2S voltage will decrease and the short term FT will increase when the system is activated. If a system airflow problem is detected, this DTC will set. When inactive, the system prevents air flow in either direction.