Circuit Description
The purpose of the secondary air injection (AIR) system is to reduce hydrocarbon (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) exhaust emissions by causing any combustible gases in the exhaust to reburn. This also causes the catalytic converters and the heated oxygen sensors (HO2S) to reach the normal operating temperatures more quickly, which will allow Closed Loop operation to occur earlier.
When the engine is started, the engine control module (ECM) commands the AIR pump relay and the AIR cut-off valve vacuum control solenoid ON, injecting clean air into the engine exhaust ports. The ECM switches the AIR system OFF when the oxygen sensors become active. The AIR cut-off valve prevents air from being drawn into the system when the AIR pump is OFF. The vacuum to the valve is controlled by the AIR cut-off valve vacuum control solenoid. A check valve close to the engine prevents hot exhaust gases from backing up into the AIR system.
Conditions for Running the DTC
| • | DTCs P0110, P0115, P0116, P0130, P0131, P0132, P0134, P0150, P0151, P0152, P0154, P0171, P0172, P0174, P0175, P0300-P0306, P0412, P0418, P0440, P0442, P0443, P0446, or P0455 are not set. |
| • | The intake air temperature (IAT) is 5-40°C (41-104°F). |
| • | The engine coolant temperature (ECT) is 18.8-105°C (65.8-221°F). |
| • | The engine is at idle. |
| • | The vehicle speed is 0 km/h (0 mph). |
| • | The secondary air injection (AIR) system is active. |
Conditions for Setting the DTC
The ECM has determined that reduced or no secondary air flow is present.
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. |
Diagnostic Aids
| • | Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector. |
| • | Using the Freeze Frame data may aid in locating an intermittent condition. If the DTC cannot be duplicated, review the information in the Freeze Frame. Try to operate the vehicle within the same Freeze Frame conditions, the RPM, the mass air flow (MAF), the vehicle speed, the temperature, etc., that were noted. This process may help in order to recreate the condition. |
| • | A Service Bay Test is available on the scan tool for the AIR System. This test will command the ECM to run the on-board diagnostic test for the AIR system. If a fault is present, the appropriate DTC will set. |
| • | Inspect the AIR pump check valve for a restriction or damage. Inspect the hoses before and after the check valve for evidence of heat damage. A heat damaged hose indicates that the check valve is stuck open allowing exhaust gas back into the AIR system. A stuck open check valve may allow exhaust gas to damage the cut-off valve. |
| • | Check the air pump for reduced flow. A pump that operates, but does not produce enough flow, will cause this DTC to set. |
| • | When testing the system for a short to ground, test the circuit on the switched side of the relay. A short can be located on the switched side of the relay and includes an air pump that draws excessive current. The air pump may have an in-rush current draw of up to 90 amps when first operating the pump. This is considered normal. The current should stabilize to about 20 amps once the pump is running. Use caution if trying to operate the pump with a fused jumper. The in-rush current required to operate the pump may open the fuse if the fuse is not designed to handle the in-rush current. |
| • | For an intermittent, refer to Intermittent Conditions . |
Step | Action | Values | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |||||||||
2 | Is DTC P0412 or P0418 also set? | -- | Go to Step 3 | |||||||||
3 |
Does the AIR pump turn ON and OFF? | -- | Go to Step 7 | Go to Step 4 | ||||||||
4 |
Does the test lamp illuminate? | -- | Go to Step 5 | Go to Step 6 | ||||||||
5 | With a test lamp connected to B+, probe the AIR pump ground circuit in the harness connector. Does the test lamp illuminate? | -- | Go to Step 23 | Go to Step 16 | ||||||||
6 |
Does the test lamp illuminate? | -- | Go to Step 15 | Go to Step 13 | ||||||||
7 |
Is the vacuum more than the specified value? | 33 kPa (10 in Hg) | Go to Step 10 | Go to Step 8 | ||||||||
8 |
Is the vacuum more than the specified value? | 33 kPa (10 in Hg) | Go to Step 9 | Go to Step 20 | ||||||||
9 |
Did you find and correct the condition? | -- | Go to Step 28 | Go to Step 25 | ||||||||
10 |
Does the valve hold vacuum? | 33 kPa (10 in Hg) | Go to Step 11 | Go to Step 26 | ||||||||
11 |
Is airflow present at the hose when the pump is running? | -- | Go to Step 19 | Go to Step 12 | ||||||||
12 |
Is airflow present at the hose when the pump is running? | -- | Go to Step 17 | Go to Step 18 | ||||||||
13 |
Did you find and correct the condition? | -- | Go to Step 28 | Go to Step 14 | ||||||||
14 | Repair the open B+ circuit to the relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 28 | -- | ||||||||
15 |
Did you find and correct the condition? | -- | Go to Step 28 | Go to Step 22 | ||||||||
16 | Repair the open/high resistance in the AIR pump ground circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 28 | -- | ||||||||
17 | Inspect the air hose between the cut-off valve and the check valve for a restriction or leak. Repair or replace as necessary. Did you find and correct the condition? | -- | Go to Step 28 | Go to Step 26 | ||||||||
18 | Inspect the air hose between the air pump and the cut-off valve for a restriction or leak. Repair or replace as necessary. Did you find and correct the condition? | -- | Go to Step 28 | Go to Step 21 | ||||||||
19 |
Did you find and correct the condition? | -- | Go to Step 28 | Go to Diagnostic Aids | ||||||||
20 | Repair the leaking or restricted vacuum supply hose. Did you complete the repair? | -- | Go to Step 28 | -- | ||||||||
21 |
Did the filter require replacement? | -- | Go to Step 28 | Go to Step 27 | ||||||||
22 |
Did you find and correct the condition? | -- | Go to Step 28 | Go to Step 24 | ||||||||
23 |
Did you find and correct the condition? | -- | Go to Step 28 | Go to Step 27 | ||||||||
24 | Replace the air pump relay. Did you complete the replacement? | -- | Go to Step 28 | -- | ||||||||
25 | Replace the AIR vacuum solenoid. Refer to Secondary Air Injection Vacuum Control Solenoid Valve Replacement . Did you complete the replacement? | -- | Go to Step 28 | -- | ||||||||
26 | Replace the AIR cut-off valve. Refer to Secondary Air Injection Shutoff Valve Replacement . Did you complete the replacement? | -- | Go to Step 28 | -- | ||||||||
27 | Replace the AIR pump. Refer to Secondary Air Injection Pump Replacement . Did you complete the replacement? | -- | Go to Step 28 | -- | ||||||||
28 |
Does the DTC run and pass? | -- | Go to Step 29 | Go to Step 2 | ||||||||
29 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |||||||||
