The control module activates the Secondary Air Injection (AIR) System by grounding both the pump relay and the vacuum control solenoid control circuits simultaneously. This energizes the AIR pump and the vacuum control solenoid. Vacuum is then applied, opening the valves. The pump then forces fresh air into the exhaust stream in order to accelerate catalyst operation. The control module will run up to 3 diagnostic tests using the pre-catalyst Heated Oxygen Sensor (HO2S) voltage and Short Term 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 an air flow condition is detected, this DTC will set. When inactive, the system prevents air flow in either direction.
CONDITIONS FOR RUNNING THE DTC
- DTCs P0102, P0103, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0171, P0172, P0300, P0440, P0442, P0443, P0446, P0449, P0506, P0507, P1111, P1112, P1114, P1115, P1121, P1122, P1133, or P1134 are not set.
- The engine run time is more than 10 seconds .
- The Engine Coolant Temperature (ECT) is between 4.5-110°C (40°F-230°F) .
- The Mass Air Flow (MAF) is between 2-25 g/s .
- The ignition voltage is more than 10 volts .
- The engine speed is more than 800 RPM .
- The fuel system is operating in DECEL control cell.
- The Intake Air Temperature (IAT) is between 4.5-70°C (40-158°F) .
- The short term fuel trim is between 0.97 to 1.03.
- The engine load is between 5-30 percent .
- The Barometric Pressure (BARO) is above 75 kPa(10.1 psi ).
- The vehicle speed is more than 40 km/h (25 mph ).
CONDITIONS FOR SETTING THE DTC
- The pre-catalyst HO2S voltage remains above a predetermined lean value during the test.
- The Short Term FT does not increase a calibrated amount during the test.
- Both conditions above exist for 3 consecutive tests.
ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Use a scan tool in order to clear the MIL and the DTC.
DIAGNOSTIC AIDS Steps 1-13
If the DTC cannot be duplicated and is determined to be intermittent, reviewing the Failure Records can be useful in determining when the DTC was last set. Also refer to Testing for Intermittent and Poor Connections in Diagrams.
A short to voltage in the pump relay control circuit can result in the AIR pump running continuously with the ignition OFF by backfeeding to ground. This will eventually result in pump failure.
An AIR pump that had become inoperative and had shown indications of having exhaust gases in the outlet port would indicate check valve failure.