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P0411



DTC P0411

DTC DESCRIPTOR

DTC P0411
Secondary Air Injection (AIR) System Incorrect Air Flow Detected

DIAGNOSTIC FAULT INFORMATION

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




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
- DTC 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
- 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 P0411 runs once per trip start up when the above conditions are met and AIR pump operation is requested.

CONDITIONS FOR SETTING THE DTC
- The difference between the predicted system pressure and the actual system pressure is more than 6 kPa.
- DTC P0411 sets within 22 seconds when the above condition is 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
1. If any other AIR DTCs are set, perform those diagnostics first.
2. Engine running, observe that the AIR Pressure Sensor parameter approximately equals BARO.
3. Engine running, enable the AIR pump with a scan tool and observe that the AIR Pressure Sensor parameter equals approximately 20-25 kPa above barometric pressure (BARO).
4. 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.

CIRCUIT/SYSTEM TESTING

IMPORTANT: Circuit/System Verification MUST be performed first or misdiagnosis may result.

1. Ignition ON, observe that the AIR pump is not activated.
- If the AIR pump is activated, test the AIR pump voltage supply circuit for a short to voltage. If the circuit tests normal, test the AIR pump relay control circuit for a short to ground. If the circuits test normal, test the AIR pump relay. If the relay and circuits test normal, replace the control module.
2. Ignition ON, enable the AIR pump with a scan tool and observe that the AIR pump is activated.
- If the AIR pump is not activated, test the AIR pump voltage supply and ground circuits for more than 2 ohms of resistance. If the circuits test normal, test both AIR pump relay voltage supply circuits for an open/high resistance or a short to ground. If the circuits test normal, test the AIR pump relay control circuit for an open/high resistance or a short to voltage. If the circuits test normal, test the AIR pump relay. If the relay and circuits test normal, test the AIR pump. If the relay, pump, and circuits test normal, replace the control module.
3. Disconnect the AIR pump outlet hose from the AIR solenoid inlet.
4. Engine running, enable the AIR pump with a scan tool and verify pressurized airflow at the hose outlet.
- If pressurized airflow is not detected, test the AIR pump inlet and outlet hoses/pipes for a restriction. If the inlet and outlet hoses/pipes test normal, replace the AIR pump.
5. Disconnect the AIR solenoid.
6. Connect a test lamp between the AIR solenoid voltage supply and ground circuit terminals.
7. Ignition ON, observe that the test lamp is not illuminated.
- If the test lamp is illuminated, test the AIR solenoid valve voltage supply circuit for a short to voltage. If the circuit tests normal, test the AIR solenoid valve relay control circuit for a short to ground. If the circuits test normal, test the AIR solenoid valve relay. If the relay and circuits test normal, replace the control module.
8. Engine running, enable the AIR solenoid with a scan tool and observe that the test lamp is illuminated.
- If the test lamp is not illuminated, test the AIR solenoid voltage supply circuit and both AIR solenoid relay voltage supply circuits for an open/high resistance or a short to ground. If the circuits test normal, test the AIR solenoid ground circuit for an open/high resistance. If the circuits test normal, test both AIR solenoid relay control circuits for and open/high resistance or a short to voltage. If the circuits test normal, test the AIR solenoid relay. If the relay and circuits test normal, replace the control module.
9. Test the AIR solenoid outlet pipe for a restriction.
- If a restriction is detected, remove the restriction or replace the pipe.
10. If all circuits and other components test OK, replace the AIR solenoid.

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.

Pump
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, replace the pump.

Solenoid Valve
1. 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 or leaking.
- If the valve operates incorrectly, leaks, or is obstructed, remove the obstruction or replace the valve.

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 and programming

REPAIR VERIFICATION
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.
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