P2440

DTC P2440

DTC DESCRIPTOR

DTC P2440
Secondary Air Injection System Switching Valve A Stuck Open

DIAGNOSTIC FAULT INFORMATION

IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection






TYPICAL SCAN TOOL DATA

AIR Pressure Sensor:

CIRCUIT/SYSTEM DESCRIPTION
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

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.

CONDITIONS FOR RUNNING THE DTC
- DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0125, P0128, P0201, P0202, P0203, P0204, P0300, P0412, P0418, P0420, P0606, P1106, P1107, P1111, P1112, P1114, P1115, P1635, P1639, P2430, P2431, P2432, P2433 are not set.
- More than 60 minutes has elapsed since the last cold start.
- The system voltage is 9-18 volts.
- The BARO parameter is more than 70 kPa.
- The MAF sensor parameter is between less than 33 g/s.
- The AIR system is commanded ON.
- 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
- 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.
- Clear the MIL and the DTC with a scan tool.

CIRCUIT/SYSTEM VERIFICATION
- 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 20-25 kPa above barometric pressure (BARO).

CIRCUIT/SYSTEM TESTING
1. Disconnect the solenoid valve.
2. 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.
3. Inspect the AIR pump inlet and outlet hoses/pipes for restrictions.
4. Inspect the solenoid valve for leaks.

COMPONENT TESTING

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.

REPAIR INSTRUCTIONS
- Secondary Air Injection (AIR) Pump Replacement
- Secondary Air Injection (AIR) Solenoid Valve Replacement
- Secondary Air Injection (AIR) Pipe Replacement
- Control Module References for control module replacement, setup and programming

REPAIR VERIFICATION
With the engine running, enable the AIR pump and observe that the AIR Pressure Sensor parameter increases to approximately 20-25 kPa above BARO.