- Secondary Air Injection (AIR) Valve Stuck Open
Diagnostic Fault Information
Typical Scan Tool Data
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 engine control module (ECM) 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:
- DTCs P0411 and P2430 run during Phase 1
- DTCs P2430 and P2440 run during Phase 2
- 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 15-20 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 ECM 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.
Conditions for Running the DTC
- DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0201-P0206, P0300, P0411, P0412, P0418, P0420, P0606, P0641, P0651, P2430, P2431, P2432, P2433 are not set.
- The system voltage is 9-18 volts .
- The BARO parameter is more than 60 kPa .
- The MAF sensor parameter is between 3-24 g/s .
- The AIR system is commanded ON.
- The start-up engine coolant temperature (ECT) is between 5-50°C (41-122°F) .
- The start-up intake air temperature (IAT) is between 5-60°C (41-140°F) .
- The conditions are stable for more than 5 seconds .
- DTC P2440 runs once per trip start up when the above conditions are met and AIR pump operation is requested.
Conditions for Setting the DTC
- The AIR system does not meet expected pressure conditions.
- DTC P2440 sets with in 8 seconds when the above conditions are met.
Action Taken When the DTC Sets
DTC P2440 is a Type B DTC.
Conditions for Clearing the MIL/DTC
DTC P2440 is a Type B DTC.
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.
- If any Secondary Air Injection System Pressure Sensor Circuit DTCs are set, perform those diagnostics first.
- Inspect the AIR hoses/pipes between the pump and the shut-off valve for leaks.
- Engine running, enable the AIR pump and observe that the AIR Pressure Sensor parameter increases to approximately 15-20 kPa above barometric pressure (BARO).
- Disconnect the solenoid valve.
- Ignition ON, observe that a test lamp installed between the solenoid voltage supply and the solenoid control circuit terminals 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.
- Inspect the AIR pump inlet and outlet hoses/pipes for restrictions.
- Inspect the solenoid valve for leaks.
- Test between the normally-closed switch terminals, if any, for 0 ohms .
- Test between the normally-open switch terminals for infinite ohms .
- Test between each switch terminal and either coil terminal for infinite ohms .
- Connect the relay coil terminals to ground and fused power to energize the relay.
- Test between each switch terminal and each coil terminal for 0 volts .
- Test between the normally-closed switch terminals, if any, for infinite ohms .
- 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 15-20 kPa above BARO.