For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### DTC Descriptor

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

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Pressure Sensor 5-Volt Reference Voltage | P2432 | P2431 | P2431 | P2430, P2431
Pressure Sensor Signal | P2432 | P2432 | P2433 | P2430, P2431
Pressure Sensor Low Reference | -- | P2433 | -- | --
Pump Voltage Supply | P0411 | P0411 | P2444 | --
Pump Ground | -- | P0411 | -- | --
Solenoid Voltage Supply | P0411 | P0411 | P2440 | --
Solenoid Ground | -- | P0411 | -- | --
Pump Relay Coil Voltage Supply | P0411, P0418 | P0411, P0418 | -- | --
Pump Relay Coil Control | P0418, P2444 | P0411, P0418 | P0418 | --
Pump Relay Switch Supply | P0411 | P0411 | -- | --
Solenoid Relay Coil Voltage Supply | P0411, P0412 | P0411, P0412 | -- | --
Solenoid Relay Coil Control | P0412, P2440 | P0411, P0412 | P0412 | --
Solenoid Relay Switch Supply | P0411 | P0411 | -- | --

#### AIR Pressure Sensor

Circuit | Normal Range | Short to Ground | Open | Short to Voltage
--- | --- | --- | --- | ---
Operating Conditions: Key ON, Engine OFF
5-Volt Reference Voltage | BARO | 41 kPa | 41 kPa | 111 kPa
Pressure Sensor Signal | BARO | 42 kPa | 41 kPa | 150 kPa
Low Reference | BARO | BARO | 145 kPa | BARO

### 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 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:

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 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, 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 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

DTC P0411 is a Type B DTC.

### Conditions for Clearing the MIL/DTC

DTC P0411 is a Type B DTC.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

#### Special Tools

J 36169-HD Heavy Duty Fused Jumper

### Circuit/System Verification

1. Verify that DTCs P0412, P0418, P2430, P2431, P2432, P2433, P2440, or P2444 are not set.

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

2. Ignition ON, command the AIR pump relay ON and OFF with a scan tool. The air pump should turn ON and OFF.

⇒ | If the air pump does not turn ON or OFF, refer to Secondary Air injection Pump Malfunction.

3. Command the AIR solenoid relay ON and OFF with a scan tool. The AIR solenoid valve should click with each command.

⇒ | If the AIR solenoid valve does not operate as specified, refer to Secondary Air Injection Solenoid Valve Malfunction.

4. Engine running, command the AIR pump relay ON with a scan tool while observing the AIR Pressure Sensor parameter. The reading should be 20-25 kPa above the BARO reading.

⇒ | If less than the specified range, refer to Secondary Air Injection System Pressure Low.

⇒ | If greater than the specified range, refer to Secondary Air Injection System Pressure High.

5. Engine running, command the AIR System ON while observing the AIR Pressure Sensor parameter. The reading should be 8-10 kPa above BARO.

⇒ | If less than the specified range, refer to Secondary Air Injection System Pressure Low.

⇒ | If greater than the specified range, refer to Secondary Air Injection System Pressure High.

6. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

### Circuit/System Testing

#### Secondary Air Injection Pump Malfunction

1. Ignition OFF, disconnect the AIR pump relay.
2. Ignition ON, verify that a test lamp does not illuminate between the controlled output circuit terminal 87 and ground.

⇒ | If the test lamp illuminates, test the controlled output circuit for a short to voltage.

3. Verify that a test lamp illuminates between the AIR pump relay coil ignition circuit terminal 86 and ground.

⇒ | If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, replace the AIR pump relay.

4. Verify that a test lamp illuminates between the AIR pump relay switch B+ circuit terminal 30 and ground.

⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the controlled output circuit for a short to ground.

5. Ignition OFF, disconnect the harness connector at the AIR pump.
6. Test for less than 2 ohms between the AIR pump ground circuit terminal B and ground.

⇒ | If greater than the specified range, test the ground circuit for an open/high resistance.

7. Connect the harness connector at the AIR pump.
8. Connect the J 36169-HD with a 50A fuse between the AIR pump relay switch B+ circuit terminal 30 and the controlled output circuit terminal 87. Verify the AIR pump is activated.

⇒ | If the AIR pump does not activate, test the controlled output circuit for an open/high resistance. If the circuit tests normal, test or replace the AIR pump.

9. Remove the J 36169-HD .
10. Connect a test lamp between the AIR pump relay coil ignition circuit terminal 86 and the AIR pump relay control circuit terminal 85.
11. Ignition ON, command the AIR pump relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒ | If the test lamp is always ON, test the AIR pump relay control circuit for a short to ground. If the circuit tests normal, replace the ECM.

⇒ | If the test lamp is always OFF, test the AIR pump relay control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

12. If all circuits test normal, replace the air pump relay.

#### Secondary Air Injection Solenoid Malfunction

1. Ignition OFF, disconnect the AIR solenoid relay.
2. Ignition ON, verify that a test lamp does not illuminate between the controlled output circuit terminal 87 and ground.

⇒ | If the test lamp illuminates, test the controlled output circuit for a short to voltage.

3. Verify that a test lamp illuminates between the AIR solenoid relay coil ignition circuit terminal 86 and ground.

⇒ | If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.

4. Verify that a test lamp illuminates between the AIR solenoid relay switch B+ circuit terminal 30 and ground.

⇒ | ⇒ If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the controlled output circuit for a short to ground.

5. Ignition OFF, disconnect the harness connector at the AIR solenoid valve.
6. Test for less than 2 ohms between the AIR solenoid ground circuit terminal 4 and ground.

⇒ | If greater than the specified range, test the ground circuit for an open/high resistance.

7. Connect the harness connector at the AIR solenoid valve.
8. Connect a 15A fused jumper wire between the AIR solenoid relay switch B+ circuit terminal 30 and the controlled output circuit terminal 87. Verify the AIR solenoid valve activates.

⇒ | If the AIR solenoid valve does not activate, test the controlled output circuit for an open/high resistance. If the circuit tests normal, test or replace the AIR solenoid valve.

9. Remove the 15A fused jumper wire.
10. Connect a test lamp between the AIR solenoid relay coil ignition circuit terminal 86 and the relay coil control circuit terminal 85.
11. Ignition ON, command the AIR solenoid relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.

⇒ | If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

12. If all circuits test normal, replace the AIR solenoid relay.

#### Secondary Air Injection System Pressure Low

1. Engine running, inspect for exhaust leaks between the AIR solenoid valve and the catalytic converter.

⇒ | If an exhaust leak is detected, repair as necessary.

2. Ignition OFF, disconnect the AIR pump relay.
3. Engine running, connect the J 36169-HD with a 50A fuse between the AIR pump relay switch B+ circuit terminal 30 and the controlled output circuit terminal 87. Verify the AIR Pressure Sensor parameter is not 20-25 kPa above BARO.

⇒ | If 20-25 kPa above BARO, replace the AIR pump relay.

4. Ignition OFF, remove the fused jumper wire and connect the AIR pump relay.
5. Remove the air inlet hose at the AIR pump.
6. Engine running, command the AIR System ON while observing the AIR Pressure Sensor parameter. Verify the reading is not 8-10 kPa above BARO.

⇒ | If 8-10 kPa above BARO, the AIR pump inlet hoses/pipes are restricted. Remove the restriction or replace the inlet hose/pipe.

7. Ignition OFF, disconnect the hose at the AIR pump outlet.
8. Disconnect the hose at the AIR solenoid valve inlet
9. Install a length of standard 1 inch I.D. (25.4 mm) hose from the AIR pump outlet to the AIR solenoid valve inlet.
10. Engine running, command the AIR system ON while observing the AIR Pressure Sensor parameter. Verify the reading is not 8-10 kPa above BARO.

⇒ | If 8-10 kPa above BARO , test/inspect the AIR pump outlet hoses/pipes for leaks or restrictions.

11. Test all AIR pump wiring and connections for less than 2 ohms. If the wiring and connections test normal, replace the AIR pump.

#### Secondary Air Injection System Pressure High

1. Ignition OFF, remove the AIR solenoid valve.
2. Connect the AIR pump outlet pipe/hose to the AIR solenoid valve.
3. Connect the AIR solenoid harness at the AIR solenoid valve.
4. Engine running, command the AIR System ON while observing the AIR Pressure Sensor parameter. The reading should be less than 11 kPa above BARO.

⇒ | If greater than the specified value, replace the AIR solenoid valve.

5. Inspect the AIR solenoid valve gaskets for proper alignment. If normal, test/inspect the cylinder head or exhaust manifold for a restriction.

### 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

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

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 Check Valve Replacement

• | Secondary Air Injection Pump Inlet Hose Replacement

• | Secondary Air Injection Pump Outlet Hose Replacement

• | Secondary Air Injection Pump Replacement

• | Control Module References for ECM replacement, setup, 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 system 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.