Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

The secondary air injection (AIR) system aids in the reduction of hydrocarbon emissions during a cold start. The system forces fresh filtered air into the exhaust stream in order to accelerate the catalyst operation. An electric air pump, the secondary AIR injection pump, provides filtered air on demand to the AIR control solenoid valve/pressure sensor assembly. The AIR control solenoid valve/pressure sensor assembly controls the flow of air from the AIR pump to the exhaust manifold. The AIR valve relay supplies the current needed to operate the AIR control solenoid valve/pressure sensor assembly. A pressure sensor is used to monitor the air flow from the AIR pump. The control module supplies the internal pressure sensor with a 5-volt reference, an electrical ground, and a signal circuit.

The AIR diagnostic uses 3 phases to test the AIR system:

1. DTCs P0411 and P2430 run during Phase 1
2. DTCs P2430 and P2440 run during Phase 2
3. DTC P2444 runs during Phase 3

During phase 1, both the AIR pump and the solenoid valve are activated. Normal secondary air function occurs. Expected system pressure is 8-10 kPa above BARO.

During phase 2, only the AIR pump is activated. The solenoid valve is closed. Pressure sensor performance and solenoid valve deactivation are tested. Expected system pressure is 20-25 kPa above BARO.

During phase 3, neither the AIR pump nor the solenoid valve is activated. AIR pump deactivation is tested. Expected system pressure equals BARO.

In all 3 phases, testing is accomplished by comparing the measured pressure against the expected pressure. The control module can detect faults in the AIR pump, AIR control solenoid valve/pressure sensor assembly, and the exhaust check valve. The pressure sensor can also detect leaks and restrictions in the secondary AIR system plumbing.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Electrical Information Reference

Scan Tool Reference

1. If any other AIR DTCs are set then perform those diagnostics first.
2. With the ignition ON and the engine OFF, observe that the AIR pump is not operating.

⇒	If the AIR pump is operating then test for the following:

•	A short to voltage in the AIR pump voltage supply circuit

•	A faulty AIR pump relay

•	A short to ground in the AIR pump relay control circuit

•	A faulty control module

3. With the ignition ON, the engine OFF, and the AIR pump enabled with a scan tool, observe that the AIR pump is operating.

⇒	If the AIR pump is not operating then test for the following:

•	Resistance greater than 2 ohms in the AIR pump voltage supply or ground circuits

•	High resistance or a short to ground in either AIR pump relay voltage supply circuit

•	High resistance or a short to voltage in the AIR pump relay control circuit

•	A faulty AIR pump relay

•	A faulty AIR pump

•	A faulty control module

4. With the engine RUNNING, enable the AIR pump with a scan tool and observe that the AIR Pressure Sensor parameter equals approximately 20-25 kPa above BARO.

⇒	If not equal to approximately 20-25 kPa above BARO then proceed with Circuit/System Testing.

5. With the engine RUNNING, enable the AIR solenoid with a scan tool and observe that the AIR Pressure Sensor parameter equals approximately 8-10 kPa above BARO.

⇒	If not equal to approximately 8-10 kPa above BARO then proceed with Circuit/System Testing.

1. With the engine RUNNING, the AIR pump outlet hose disconnected from the AIR solenoid inlet, and the AIR pump enabled with a scan tool, observe pressurized airflow at the hose outlet.

⇒	If pressurized airflow is not detected then test the AIR pump inlet and outlet hoses/pipes for a restriction or a faulty pump.

2. With the ignition ON, the engine OFF, and the AIR solenoid substituted with a test lamp, observe that the test lamp is not illuminated.

⇒	If the test lamp is illuminated then test for the following:

•	A short to voltage in the AIR solenoid valve voltage supply circuit

•	A short to ground in the AIR solenoid valve relay control circuit

•	A faulty AIR solenoid valve relay

•	A faulty control module

3. With the engine RUNNING, the AIR solenoid substituted with a test lamp, and the AIR solenoid enabled with a scan tool, observe that the test lamp is illuminated.

⇒	If the test lamp is not illuminated then test for the following:

•	High resistance or a short to ground in the AIR solenoid voltage supply circuit or either AIR solenoid relay voltage supply circuit

•	High resistance in the AIR solenoid ground circuit

•	A faulty AIR solenoid relay

•	High resistance or a short to voltage in the AIR solenoid relay control circuit

•	A faulty control module

4. Test the AIR solenoid outlet pipe for a restriction.

⇒	If a restriction is detected then remove the restriction or replace the pipe.

5. If all other circuits and components test OK then replace the AIR solenoid.

1. Connect the AIR pump to fused battery voltage and ground and observe pressurized airflow at the pump outlet.

⇒	If pressurized airflow is not observed then replace the pump.

2. Connect the relay coil connections to fused battery voltage and ground. Measure resistance through the relay contacts at 0 ohms.

⇒	If resistance measures more than 0 ohms then replace the relay.

3. Apply fused battery voltage and ground to the solenoid and verify that the valve opens and closes completely as voltage is applied to and removed from the solenoid. Observe that the valve is not obstructed.

⇒	If the valve operates incorrectly or is obstructed then remove the obstruction or replace the valve.

1. With the ignition ON and the engine OFF, observe that the AIR pump is not operating.
2. With the engine RUNNING, enable the AIR solenoid with a scan tool and observe that the AIR Pressure Sensor parameter equals approximately 8-10 kPa above BARO.
3. With the engine RUNNING, enable the AIR pump with a scan tool and observe that the AIR Pressure Sensor parameter equals approximately 20-25 kPa above BARO.