Refer to Engine Controls Schematics
Secondary Air Injection (AIR) Pump Motors w/NB6-California Emissions
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Circuit Description
The two AIR pumps used on this vehicle lower tail pipe emissions during start-up. The AIR system consists of the following items:
| • | The AIR pumps |
| • | The check valves |
| • | The vacuum solenoid |
| • | The system hoses and pipes |
| • | The AIR relays, fuses, and related wiring |
The PCM uses the AIR relays to control the AIR pumps. The PCM also controls the AIR vacuum solenoid that supplies vacuum to the AIR check valves. With the AIR system inactive, the AIR check valves prevent air flow in either direction. With the AIR system active, the PCM applies ground to one of the AIR relays, and the vacuum solenoid. Then the PCM applies ground to the other AIR relay. Fresh air flows from the pumps, through the system hoses, pass the check valves, and into the exhaust stream. The air helps the catalyst to quickly get to a working temperature; thus lowering the tail pipe emissions on a start-up. The PCM tests the following AIR system components:
| • | 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 relays (DTC P0418, and DTC P0419) |
| • | AIR vacuum control solenoid (DTC P412) |
The PCM runs two tests to diagnose the AIR system: Passive, and Active. Both tests involve a response from the fuel control HO2 sensors (HO2S bank 1 sensor 1 and HO2S bank 2 sensor 2). The Passive test consists of two 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 PCM determines that HO2S bank 2 sensor 1 did not respond as expected during the tests, DTC P1416 will set. For further information concerning the AIR system and system tests, refer to Secondary Air Injection System Description .
Conditions for Running the DTC
Passive Tests:
| • | The engine is running. |
| • | The engine speed is more than 600 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 35 g/s. |
| • | The air fuel ratio is more than 12.5:1 |
| • | The ECT is between 0°C and 108°C (32°F and 226°F). |
| • | The IAT is between 0°C and 60°C (32°F and 140°F). |
| • | The power enrichment, or deceleration fuel cut-off is not active. |
Active Tests:
| • | The engine is running. |
| • | The engine speed is more than 600 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 35 g/s. |
| • | The fuel system is in closed-loop operation. |
| • | The EVAP purge is active. |
| • | The ECT is above 68°C (154°F). |
Conditions for Setting the DTC
Passive Tests:
| • | During the operation of the AIR pumps, HO2S bank 1 sensor 1 voltage remains above 470 mV for 20 seconds (450 mV for 7 seconds on a hot start). |
| OR |
| • | When the AIR pumps are turned OFF, HO2S bank 1 sensor 1 voltage remains below 700 mV for 25 seconds. |
| • | The PCM initiates the active test due to a failed or an indeterminate passive test. |
Active Test:
| • | A failed or an indeterminate passive test |
| • | The HO2S bank 1 sensor 1 voltage remains above 35 mV. |
| • | The PCM detects a failed passive test and two failed active tests. |
| OR |
| • | The PCM records an indeterminate passive test and three active tests. |
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test runs and fails. |
| • | The PCM stores the conditions present when the DTC set as Freeze Frame/Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn the MIL OFF after the third consecutive trip in which the diagnostic runs and passes. |
| • | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using the scan tool Clear DTC Information function. |
Diagnostic Aids
If the condition is intermittent, refer to Intermittent Conditions .
Step | Action | Values | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||||||
2 | Are any of the following DTCs set?
| -- | Go to applicable DTC table first | |||||||||
3 | Check for a blown AIR pump bank 2 fuse. Is the fuse blown? | -- | ||||||||||
4 | With the scan tool installed, command the AIR pump bank 2 ON and OFF. Does the AIR pump turn ON and OFF? | -- | ||||||||||
5 | Is the AIR pump running continuously? | -- | ||||||||||
6 |
Is the AIR pump running? | -- | ||||||||||
7 |
Did you find and correct the condition? | -- | ||||||||||
8 |
Did you find and correct the condition? | -- | ||||||||||
9 | Remove the AIR relay. Is the AIR pump running? | -- | ||||||||||
10 | Locate and repair the short to voltage in the circuit between the AIR relay and the AIR pump. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |||||||||
11 |
Important: Be sure the replace the AIR pump fuse. Did you find and correct the condition? | -- | ||||||||||
12 |
Is air flow present? | -- | ||||||||||
13 |
Is the HO2S bank 2 sensor 1 voltage below the specified value? | 250 mV | ||||||||||
14 |
Did you find and correct the condition? | -- | ||||||||||
15 |
Did you find and correct the condition? | -- | ||||||||||
16 | Replace the AIR pump. Refer to AIR Pump Replacement bank 2. Is the action complete? | -- | -- | |||||||||
17 | Replace the AIR relay. Is the action complete? | -- | -- | |||||||||
18 | Replace the vacuum line between the AIR vacuum solenoid and the AIR shut-off valve. Is the action complete? | -- | -- | |||||||||
19 | Replace the AIR shut-off valve. Is the action complete? | -- | -- | |||||||||
20 |
Operate the vehicle within the Fail Records conditions. Does the scan tool indicate that DTC P1416 passed? | -- | System OK |
