GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2009 🢒 LaCrosse 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 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 Descriptor

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

AIR Pump Control (Voltage Supply)

P0411

P0411

P2444

--

AIR Pump Ground

--

P0411

--

--

AIR Pump Relay Coil Ignition Supply

P0411, P0418

P0411, P0418

--

--

AIR Pump Relay Coil Control

P0418, P2444

P0411, P0418

P0418

--

AIR Pump Relay Switch B+ Supply

P0411

P0411

--

--

AIR Solenoid Control (Voltage Supply)

P0411

P0411

P2440

--

AIR Solenoid Ground

--

P0411

--

--

AIR Solenoid Relay Coil Ignition Supply

P0411, P0412

P0411, P0412

--

--

AIR Solenoid Relay Coil Control

P0412, P2440

P0411, P0412

P0412

--

AIR Solenoid Relay Switch B+ Supply

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 powertrain control module (PCM) supplies the internal pressure sensor with a 5-volt reference, a low reference, and a signal circuit. The signal circuit provides the PCM 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
    • DTC 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 approximately 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 PCM 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

P0411

    • DTC P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0201-P0206, P0300-P0306, P0412, P0418, P0420, P0606, P2430, P2431, P2432, P2433 are not set.
    • More than 120 minutes has elapsed since the last cold start.
    • The system voltage is 9-18 volts.
    • 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 BARO parameter is more than 70 kPa.
    • The MAF sensor parameter is between 3-24 g/s.
    • 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 AIR pump operation is requested.

P0412 or P0418

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

P2440

    • DTC P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0201-P0206, P0300-P0306, P0411, P0412, P0418, P0420, P0606, P0641, P0651, P2430, P2431, P2432, P2433 are not set.
    • More than 120 minutes has elapsed since the last cold start.
    • The system voltage is between 9-18 volts.
    • The BARO is greater than 60 kPa.
    • The MAF sensor is 3-24 g/s.
    • The start-up engine coolant temperature (ECT) is 5-50°C (41-122°F).
    • The start-up intake air temperature (IAT) is 5-60°C (41-140°F).
    • The AIR system is commanded ON.
    • The conditions are stable for greater than 5 seconds.
    • DTC P2440 runs once per trip start-up when the above conditions are met and the AIR pump operation is requested.

P2444

    • DTC P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0201-P0206, P0300-P0306, P0411, P0412, P0418, P0420, P0606, P0641, P0651, P2430, P2431, P2432, P2433 are not set.
    • More than 120 minutes has elapsed since the last cold start.
    • The system voltage is between 9-18 volts.
    • The BARO is greater than 70 kPa.
    • The MAF sensor is less than 33 g/s.
    • The start-up engine coolant temperature (ECT) is 5-50°C (41-122°F).
    • The start-up intake air temperature (IAT) is 5-60°C (41-140°F).
    • The AIR system is commanded ON.
    • The conditions are stable for greater than 5 seconds.
    • DTC P2444 runs once per trip start-up when the above conditions are met and the 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 5 kPa.
    • DTC P0411 sets during phase 1 and within 22 seconds when the above condition is met.

P0412 or P0418

    • The PCM determines that the actual and expected states of the AIR solenoid relay and AIR pump relay control circuits do not match.
    • DTCs P0412 or P0418 set when the above condition exists for greater than 2 seconds.

P2440

    • The difference between the predicted system pressure and the actual system pressure is more than 3 kPa.
    • DTC P2440 sets during phase 2 and when the above condition exists for greater than 8 seconds.

P2444

    • The difference between the predicted system pressure and the actual system pressure is more than 3 kPa.
    • DTC P2444 sets during phase 3 and when the above condition exists for greater than 5 seconds.

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
    •  Relay Replacement

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 valve should click with each command.
    4. ⇒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. Observe the AIR Pressure Sensor parameter. The reading should be 15-22 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 85 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 and/or the AIR solenoid 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 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 Jumper 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.
    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. Remove the J 36169-HD Jumper .
  10. Connect a test lamp between the AIR pump relay coil ignition circuit terminal 85 and the AIR pump relay control circuit terminal 86.
  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.
    12. ⇒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 PCM.
    ⇒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 PCM.
  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.
    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 85 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 for a short to ground on the solenoid relay controlled output circuit terminal 87. If the circuit tests normal, replace the AIR solenoid relay or the AIR pump relay.
  4. Verify that a test lamp illuminates between the AIR solenoid 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 for a short to ground.
  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 secondary AIR solenoid.
  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 is activated.
    9. ⇒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.
  9. Remove the 15A fused jumper wire.
  10. Connect a test lamp between the AIR solenoid relay coil ignition circuit terminal 85 and the relay coil control circuit terminal 86.
  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.
    12. ⇒If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the PCM.
    ⇒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 PCM.
  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.
    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 Jumper 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 15-22 kPa above BARO.
    4. ⇒If 15-22 kPa above BARO, replace the AIR pump relay.
  4. Ignition OFF, remove the fused J 36169-HD 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.
    7. ⇒If 8-10 kPa above BARO, the AIR pump inlet hose/pipe assembly is restricted. Remove the restriction or replace the hose/pipe assembly.
  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 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 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.
  2. Connect the AIR injection 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 solenoid relay ON with a scan tool while observing the AIR Pressure Sensor parameter. The reading should be less than 11 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 AIR solenoid outlet pipe, and exhaust manifold.

Repair Instructions
    •  Secondary Air Injection Pump Replacement
    •  Secondary Air Injection Shut-Off Valve Outlet Pipe/Hose Replacement
    •  Secondary Air Injection Shutoff Valve Replacement
    •  Relay Replacement
    •  Control Module References for 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 solenoid relay ON with a scan tool. The AIR Pressure Sensor parameter should be 8-10 kPa above BARO.
  6. Engine running, command the AIR pump relay ON with a scan tool. The AIR Pressure Sensor parameter should be 15-22 kPa above BARO.