Circuit Description
The secondary air injection (AIR) pump used on this vehicle lowers the tail pipe emissions during start-up. The AIR system consists of the following components:
| • | The AIR pump |
| • | The shut-off valves |
| • | The vacuum control solenoid valve |
| • | The system hoses and pipes |
| • | The AIR relay, the fuses, and the related wiring |
The powertrain control module (PCM) uses the AIR relay in order to control the AIR pump. The PCM also controls the AIR vacuum control solenoid valve that supplies the vacuum to the AIR shut-off valves. With the AIR system inactive, the AIR shut-off valves prevent air flow in either direction. With the AIR system active, the PCM applies ground to the AIR relay and to the vacuum control solenoid valve. Fresh air flows from the pump, through the system hoses, past the shut-off valves, and into the exhaust stream. The air helps the catalyst to quickly get to a working temperature, lowering the tail pipe emissions during a start-up.
The PCM runs a passive test and an active test in order to diagnose the AIR system. Both tests involve a response from the fuel control HO2S (HO2S bank 1 sensor 1 and HO2S bank 2 sensor 2). The passive test consists of 2 parts. If both passive tests pass, the PCM takes no further action. If either part of the passive test fails or is inconclusive, the PCM initiates the active tests. If the active test does not pass, the PCM may set one or more of the following DTCs:
| • | The overall AIR system, including both banks--Any problems detected here will result in DTC P0410. |
| • | The AIR system bank 1 (DTC P1415) |
| • | AIR system bank 2 (DTC P1416) |
| • | AIR relay (DTC P0418) |
| • | AIR vacuum control solenoid valve (DTC P0412) |
For further information concerning the AIR system and the system tests, refer to Secondary Air Injection System Description .
Conditions for Running the DTC
Passive Tests
| • | DTCs P0102, P0103 P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0151, P0152, P0153, P0154, P0155, P0157, P0158, P0161, P0200, P0300, P0335, P0336, P0351, P0352, P0353, P0354, P0355, P0356, P0357, P0358, P0506, P0507, P1133, P1134, P1138, or P1171 are not set. |
| • | The engine is running for more than 2 seconds. |
| • | The engine speed is more than 1000 RPM. |
| • | The throttle is steady. |
| • | The engine load is less than 80 percent. |
| • | The system voltage is more than 10.5 volts. |
| • | The mass air flow (MAF) is less than 35 g/s. |
| • | The air/fuel ratio is more than 11.1:1. |
| • | The engine coolant temperature (ECT) is between 0-108°C (32-226°F). |
| • | The intake air temperature (IAT) is between 0-72.5°C (32-162.5°F). |
| • | The power enrichment, or deceleration fuel cut-off (DFCO) is not active. |
| • | The start-up ECT is between 5-80°C (41-176°F). |
Active Tests
| • | The engine is running. |
| • | The engine speed is more than 1000 RPM. |
| • | The throttle is steady. |
| • | The engine load is less than 80 percent. |
| • | The system voltage is more than 10.5 volts. |
| • | The MAF is less than 75 g/s. |
| • | The fuel system is in Closed-Loop operation. |
| • | The EVAP purge is active. |
| • | The ECT is above 68°C (154°F). |
| • | The short term fuel trim is between -3 and +3 percent. |
| • | The fuel trim is in cells 4, 5, or 6. |
Conditions for Setting the DTC
Passive Tests
| • | During the operation of the AIR pump, the HO2S voltage remains above 300 mV for 12 seconds, and above 350 mV for 9 seconds during a hot start. |
| or |
| With the AIR pump commanded OFF, the HO2S voltage remains below 600 mV for 25 seconds. |
| • | The PCM initiates the active test due to a failed or an indeterminate passive test. |
Active Tests
| • | A failed or an indeterminate passive test has occurred. |
| • | The HO2S voltage remains above 35 mV. |
| • | The PCM detects a failed passive test and 2 failed active tests. |
| or |
| The PCM records an indeterminate passive test and 3 active tests. |
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
| • | An intermittent may be caused by any of the following conditions: |
| - | Low system air flow may cause this DTC to set. |
| - | Excessive exhaust system back-pressure |
| - | Moisture, water, or debris ingestion into the AIR pump. |
| - | Pinched, kinked, heat damaged, or deteriorated hoses or vacuum lines |
| - | Restrictions in the pump inlet, duct, or filter |
| • | If the condition is intermittent, refer to Intermittent Conditions . |
Step | Action | Value(s) | Yes | No | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||||||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |||||||||||
2 |
Does the HO2S voltage drop below the specified value? | 100 mV | Go to Diagnostic Aids | Go to Step 3 | ||||||||||
3 |
Does the vacuum indicate more than the specified value? | 12 in Hg | Go to Step 4 | Go to Step 6 | ||||||||||
4 | Turn OFF the ignition. Connect a vacuum pump to the affected bank shut-off valve and apply 10 inches of vacuum to the valve. Does the valve hold vacuum for the specified amount of time? | 30 seconds. | Go to Step 5 | Go to Step 8 | ||||||||||
5 | Inspect all pipes/hoses for the following conditions:
Did you locate the condition? | -- | Go to Step 7 | Go to Step 8 | ||||||||||
6 | Replace the vacuum line between the AIR solenoid valve and the affected bank AIR shut-off valve. Did you complete the replacement? | -- | Go to Step 9 | -- | ||||||||||
7 | Repair the condition. Refer to Secondary Air Injection Pump Intermediate Pipe/Hose Replacement - Bank 1 , Secondary Air Injection Pump Intermediate Pipe/Hose Replacement - Bank 2 , or Secondary Air Injection Crossover Pipe/Hose Replacement . Did you complete the repair? | -- | Go to Step 9 | -- | ||||||||||
8 | Replace the AIR shut-off valve for the affected bank. Refer to Secondary Air Injection Shutoff Valve Replacement - Bank 1 or Secondary Air Injection Shut-Off Valve Outlet Pipe/Hose Replacement - Bank 2 . Did you complete the replacement? | -- | Go to Step 9 | -- | ||||||||||
9 |
Does the DTC run and pass? | -- | Go to Step 10 | Go to Step 2 | ||||||||||
10 | Observe the stored information in Capture Info. with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |||||||||||
