GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2009 🢒 TrailBlazer - 4WD 🢒 Engine 🢒 Engine Controls and Fuel - 4.2L 🢒 DTC P0411, P0412, P0418, P2440, or P2444

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 Descriptors

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

DTC P0412 : Secondary Air Injection (AIR) Solenoid Control Circuit

DTC P0418 : Secondary Air Injection (AIR) Pump Control Circuit

DTC P2440 : Secondary Air Injection (AIR) System Shut-Off Valve Stuck Open

DTC P2444 : Secondary Air Injection (AIR) System Pump Stuck ON

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Pump Control

P0411

P0411

P0411

--

Pump Ground

--

P0411

--

--

Pump Relay Coil Ignition

P0412, P0418

P0418

P0690

--

Pump Relay Control

P0418

P0418

P0690, P2431

--

Pump Relay Switch B+

P0411

P0411

--

--

Solenoid Control

P0411

P0411

P0440

--

Solenoid Ground

--

P0411

--

--

Solenoid Relay Coil Ignition

P0412

P0412

P0690

--

Solenoid Relay Control

P0412

P0412

P0412, P0690

--

Solenoid Relay Switch B+

P0411

P0411

--

--

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. The secondary AIR injection pump provides filtered air on demand to the AIR solenoid check valve assembly. The AIR solenoid valve assembly controls the flow of air from the AIR pump to the exhaust manifold. The AIR pump relay supplies the current needed to operate the AIR pump. The AIR solenoid valve assembly has an integral check valve, pressure sensor, and solenoid valve. The pressure sensor monitors the air flow pressure from the AIR pump. The engine control module (ECM) supplies the internal pressure sensor with a 5-volt reference, a low reference, and a signal circuit. The signal circuit provides the control module with a voltage relative to internal AIR pressure changes.

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 8-15 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 control module can detect faults in the AIR pump, AIR solenoid, pressure sensor, 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

P0411

    • DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0125, P0128, P0201-P0204, P0300, P0301-P0304, P0412, P0418, P0420, P0606, P0641, P0651, P1106, P1111, P1112, P1114, P1115, 1635, P1639, P2430, P2431, P2432, P2433, P2440, 2444 are not set.
    • The system voltage is between 9-18 volts.
    • The intake air temperature (IAT) is greater than 5°C (41°F).
    • The BARO parameter is more than 70 kPa.
    • The MAF sensor parameter is less that 33 g/s.
    • More than 60 minutes has elapsed since the last cold start.
    • The AIR system is commanded ON.
    • The conditions are stable for greater than 5 seconds.
    • DTC P0411 runs once per trip start up when the above conditions are met and the AIR pump operation is requested.

P0412 or P0418

    • The system voltage is between 9-18 volts.
    • This DTC runs on a 100 ms loop.
    • DTCs P0412 and P0418 run continuously when the above conditions are met.

P2440

    • 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 P2440 runs once per trip start up when the above conditions are met and AIR pump operation is requested.

P2444

    • 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 P2444 runs once per trip start up when the above conditions are met and AIR pump operation is requested.

Conditions for Setting the DTC

P0411

    • 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.

P0412 or P0418

    • The actual and expected states of the AIR solenoid relay control circuit, DTC P0412, or the AIR pump relay control circuit, DTC P0418, do not match.
    • The condition exists for at least 2 seconds.

P2440

    • The AIR system does not meet expected pressure conditions.
    • DTC P2440 sets with in 8 seconds when the above conditions are met.

P2444

    • The measured AIR pressure is more than expected.
    • DTC P2444 sets within 5 seconds when the above condition is met.

Action Taken When the DTC Sets
    • DTCs P0411, P0412, P0418, and P2440 are Type B DTCs.
    • DTC P2444 is a Type A DTC.

Conditions for Clearing the MIL/DTC
    • DTCs P0411, P0412, P0418, and P2440 are Type B DTCs.
    • DTC P2444 is a Type A DTC.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Secondary Air Injection System Description

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

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 P2430, P2431, P2432, or P2433 are not set.
    2. ⇒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.
    3. ⇒If the AIR pump does not turn ON or OFF, refer to Secondary Air Injection Pump Malfunction.
  3. Command the AIR solenoid ON and OFF with a scan tool. The AIR solenoid should open and close with each command. A clicking sound should be heard or felt.
    4. ⇒If the solenoid does operate as specified, refer to Secondary Air Injection Solenoid Valve Malfunction.
  4. Engine running, command the AIR pump relay ON while observing the AIR Pressure Sensor parameter. The reading should be 20-25 kPa above the BARO reading.
    5. ⇒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.
    6. ⇒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.
    3. ⇒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.
    4. ⇒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.
    5. ⇒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 terminal 87 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.
    7. ⇒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 Fused Jumper with a 60A fuse between the AIR pump relay switch B+ circuit terminal 30 and the controlled output circuit terminal 87. Verify the AIR pump is activated.
    9. ⇒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. Verify that a test lamp does not illuminate between the AIR pump relay coil ignition circuit terminal 86 and the AIR pump relay control circuit terminal 85.
    10. ⇒If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.
  10. Remove the test lamp.
  11. Ignition ON, command the AIR pump relay ON with a scan tool. Verify the scan tool AIR Pump Relay Ckt. Short Volts Test Status parameter is OK.
    12. ⇒If not the specified value, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  12. Install a 3A fused jumper wire between the control circuit terminal 85 and the ignition circuit terminal 86. Command the AIR pump relay ON with a scan tool. Verify the scan tool AIR Pump Relay Ckt. Short Volts Test Status parameter is Fault.
    13. ⇒If not the specified value, test the control circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  13. 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 85 and ground.
    3. ⇒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.
    4. ⇒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, test the controlled output circuit terminal 85 for a short to ground. If the circuit tests normal, replace the AIR solenoid relay.
  4. Verify that a test lamp illuminates between the AIR solenoid relay switch ignition circuit terminal 87 and ground.
    5. ⇒If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
  5. Ignition OFF, disconnect the harness connector at the AIR solenoid.
  6. Test for less than 2 ohms between the AIR solenoid ground circuit terminal 4 and ground.
    7. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the harness connector at the AIR solenoid.
  8. Connect a 15A fused jumper wire between the AIR solenoid relay switch ignition circuit terminal 87 and the controlled output circuit terminal 85. Verify the AIR solenoid is activated.
    9. ⇒If the AIR solenoid does not activate, test the controlled output circuit for an open/high resistance. If the circuit tests normal, test or replace the AIR solenoid.
  9. Verify that a test lamp does not illuminate between the AIR solenoid relay coil ignition circuit terminal 86 and the relay coil control circuit terminal 30.
    10. ⇒If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.
  10. Remove the test lamp.
  11. Command the secondary AIR solenoid ON with a scan tool. Verify the scan tool AIR Sol parameter Ckt. Short Volts Test Status parameter is OK.
    12. ⇒If not the specified value, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  12. Install a 3A fused jumper wire between the control circuit terminal 30 and the ignition circuit terminal 86. Command the AIR Solenoid ON with a scan tool. Verify the scan tool AIR Sol Ckt. Short Volts Test Status parameter is Fault.
    13. ⇒If not the specified value, test the control circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  13. 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.
    2. ⇒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 Fused Jumper with a 60A 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.
    4. ⇒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 from 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.
    7. ⇒If 8-10 kPa above BARO, the AIR pump inlet hoses/pipes are restricted. Remove the restriction or replace the hose/pipe.
  7. Ignition OFF, disconnect the hose at the AIR pump outlet.
  8. Disconnect the hose quick-connect from 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 with a scan tool while observing the AIR Pressure Sensor parameter. Verify the reading is not 8-10 kPa above BARO.
    11. ⇒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 and the hoses/pipes are OK, 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 at the AIR solenoid valve.
  3. Connect the AIR solenoid wiring harness to the AIR solenoid valve.
  4. Engine running, command the AIR system ON with a scan tool while observing the AIR Pressure Sensor parameter. The reading should be less than 7 kPa above BARO.
    5. ⇒If greater than the specified value, replace the AIR solenoid valve.
  5. Inspect the AIR solenoid valve gasket for proper alignment. If normal, test/inspect the exhaust manifold for a restriction.

Repair Instructions
    •  Secondary Air Injection Pump Replacement
    •  Secondary Air Injection Solenoid Valve Replacement
    •  Secondary Air Injection Pump Hose Replacement
    •  Control Module References for engine control module (ECM) replacement, setup, and programming

Repair Verification
  1. Install any components or connectors that have been removed or replaced during diagnosis.
  2. Perform any adjustment, programming, or setup procedures that are required when a component or module is removed or replaced.
  3. Clear the DTCs.
  4. Turn OFF the ignition for 90 seconds.
  5. Engine running, command the AIR system ON with a scan tool. The AIR Pressure Sensor parameter should be between 20-25 kPa above BARO.
  6. Engine running, command the AIR pump relay ON with a scan tool. The AIR Pressure Sensor parameter should be between 8-10 kPa above BARO.