Circuit Description
A secondary air injection (AIR) pump is used on this vehicle in order to lower the tail pipe emissions on start-up. The powertrain control module (PCM) supplies a ground to the AIR pump relay, which energizes the AIR pump and the AIR solenoid valve. Engine vacuum is applied to the AIR Shut-off valve when the AIR solenoid is energized. The engine vacuum opens the AIR shut-off valve which allows air to flow to the exhaust manifolds.
The PCM monitors the heated oxygen sensor (HO2S) voltages to diagnose the AIR system.
During the AIR test, the PCM activates the AIR pump during Closed Loop operation. When the AIR system is activated, the PCM monitors the heated oxygen sensor (HO2S) voltages and short term fuel trim values for both banks of the engine. If the AIR system is operating properly, the HO2S voltages should go low and the short term fuel trim should go high.
If the PCM determines that the HO2S voltages for both banks did not respond as expected during the tests, diagnostic trouble code (DTC) P0410 sets. If only one sensor responded, the PCM sets either a DTC P1415 for bank 1 or P1416 for bank 2 in order to indicate on which bank the AIR system is inoperative.
Conditions for Running the DTC
| • | DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0131 , P0132, P0133, P0134 , P0135-P0141-P0155, P0137, P0138, P0140, P0151, P0152, P0153, P0154, P0157, P0158, P0160, P0161, P0171, P0172 , P0174, P0175, P0200, P0300, P0335, P0336, P0351-P0358, P0443, P0446, P0449, or P1258 are not set. |
| • | The start-up coolant temperature is below 80°C (176°F). |
| • | The engine run time is more than 2 seconds. |
| • | The engine load is less than 23 percent. |
| • | The engine air flow is less than 18 g/s. |
| • | The engine speed is more than 75 RPM. |
| • | The ignition voltage is more than 11.7 volts. |
| • | The air/fuel ratio is 14.7:1. |
| • | The engine coolant temperature (ECT) is between 70-110°C (158-230°F). |
| • | The intake air temperature (IAT) is between 2-100°C (36-212°F). |
| • | The fuel system is not operating in power enrichment or deceleration fuel cut-off. |
| • | The short term fuel trim is in cells 5 or 6. |
| • | The vehicle speed is more than 25 km/h (15 mph). |
Conditions for Setting the DTC
The HO2S voltage does not go below 222 mV for 1.2 seconds or more, and the short term fuel trim does not go above a predetermined amount.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/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
| • | Casting flash in the exhaust manifold may restrict the amount of air flow necessary to affect the HO2S voltage. If you suspect this, remove the air pipe from the manifold and inspect the passage. |
| • | If you cannot duplicate the DTC, use the Freeze Frame/Failure Records in order to locate an intermittent condition in the following ways: |
| - | Use the information included in the Freeze Frame/Failure Records in order to determine how many miles since the DTC set. |
| - | Use the Fail Counter and Pass Counter in order to determine how many ignition cycles the diagnostic test reported as a pass or a fail. |
| - | Operate the vehicle within the same Freeze Frame conditions that you observed in order to isolate when the DTC failed. Use the following conditions for your tests: |
| • | The RPM |
| • | The load |
| • | The vehicle speed |
| • | The temperature |
| • | For an intermittent condition, refer to Intermittent Conditions . |
Test Description
The number below refers to the step number on the diagnostic table.
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 |
Important: Before proceeding with this diagnostic table ensure that the AIR pump is operating and that air is present at the outlet of the AIR shut-off valve. If the AIR pump is inoperative, and if air is not present at the outlet of the AIR shut-off valve, refer to DTC P0410 for further diagnosis.
Does the HO2S voltage drop below the specified value? | 350 mV | Go to Diagnostic Aids | Go to Step 3 | ||||||||
Inspect all hoses and pipes for the following conditions:
Are all of the above OK? | -- | Go to Step 4 | Go to Step 6 | |||||||||
4 |
Is air present at the hose outlet? | -- | Go to Step 7 | Go to Step 5 | ||||||||
5 | Repair the restriction or blockage in AIR hoses/pipes between the left exhaust manifold and the point where the system branches to both sides of the engine. Did you complete the repair? | -- | Go to Step 8 | -- | ||||||||
6 | Repair the condition found. Is the action complete? | -- | Go to Step 8 | -- | ||||||||
7 | Replace the appropriate check valve. Refer to Secondary Air Injection Check Valve Replacement - Bank 1 or Secondary Air Injection Check Valve Replacement - Bank 2 . Did you complete the replacement? | -- | Go to Step 8 | -- | ||||||||
8 |
Does the scan tool indicate that this test ran and passed? | -- | Go to Step 9 | Go to Step 2 | ||||||||
9 | Use a scan tool in order to observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |||||||||
