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 powertrain control module (PCM) 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 15-22 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 PCM 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.

DTC P2440 is a Type B DTC.

DTC P2440 is a Type B DTC.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Important: This DTC may set if the ignition is turned OFF and the engine is restarted within approximately 30 seconds during Phase 2 of the AIR diagnostic test.

1. Verify that DTCs P0412, P0418, P2430, P2431, P2432, P2433, or P2444 are not set.

⇒	If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.

2. Inspect the AIR hoses/pipes between the pump and the shut-off valve for leaks.
3. Engine running, enable the AIR pump and observe that the AIR Pressure Sensor parameter increases to approximately 15-22 kPa above barometric pressure (BARO).
4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Disconnect the solenoid valve.
2. Ignition ON, observe that a test lamp installed between the AIR solenoid voltage supply circuit terminal 6 and the AIR solenoid control circuit terminal 4 is not illuminated.

⇒	If the test lamp is illuminated, test for a short to voltage on the solenoid voltage supply circuit. If the circuit tests normal, test or replace the relay.

3. Inspect the AIR pump inlet and outlet hoses/pipes for restrictions.
4. Inspect the solenoid valve for leaks.

⇒	If solenoid valve inspects OK, replace the AIR pump.

Relay Test

1. Test between the normally-closed switch terminals, if any, for 0 ohms.
2. Test between the normally-open switch terminals for infinite ohms.
3. Test between each switch terminal and either coil terminal for infinite ohms.
4. Connect the relay coil terminals to ground and fused power to energize the relay.
5. Test between each switch terminal and each coil terminal for 0 volts.
6. Test between the normally-closed switch terminals, if any, for infinite ohms.
7. Test between the normally-open switch terminals for 0 ohms.

With the engine running, enable the AIR pump and observe that the AIR Pressure Sensor parameter increases to approximately 15-22 kPa above BARO.