Refer to Engine Controls Schematics
Secondary Air Injection (AIR) Pump Motors w/NB6-California Emissions
.
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 system hoses and piping |
| • | 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. After a few seconds, the PCM applies
ground to the other AIR relay. Fresh air flows from the pumps, through the
system hoses, past the check valves, and into the exhaust stream. The air
helps the catalyst to reach a working temperature quickly, thus lowering
the tail pipe emissions on start-up. The PCM tests the following AIR system
components:
| • | The overall AIR system including both banks (DTC P0410). |
| • | AIR system bank 1 (DTC P1415) |
| • | AIR system bank 2 (DTC P1416) |
| • | AIR relays (DTC P0418, and DTC P0419) |
| • | AIR vacuum control solenoid (DTC P0412) |
The PCM runs two tests to diagnose the AIR system: Passive, and Active.
Both tests contain two parts, and involve a response from the fuel control
HO2 sensors (HO2S bank 1 sensor 1 and HO2S bank 2 sensor 2).
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 the HO2S voltages did not respond as expected
during the tests, DTC P0410 is 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 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 5°C-110°C (41°F-230°F). |
| • | The IAT is between 5°C-60°C (41°F-140°F). |
| • | The power enrichment, or the deceleration fuel cut-off function
is not active. |
Active Tests:
| • | 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 more than 68°C (154°F). |
Conditions for Setting the DTC
Passive Tests:
| • | During the operation of the AIR pumps, the HO2S voltage for both
fuel control sensors is above 250 mV for 20 seconds, or 200 mV
for 7 seconds on a hot start. |
| • | When the AIR pumps are turned OFF, the HO2S voltage for both fuel
control sensors is below 740 mV for 20 seconds, or 7 seconds
on a hot start. |
| • | The condition is present for 3 occurrences. |
Active Test:
The HO2S voltage for both fuel control sensors is above 250 mV
for 3 occurrences.
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
Reviewing the Fail Records vehicle mileage since the diagnostic test
last failed may assist in diagnosing the condition. The information may help
in determining how often the condition occurs caused the DTC to set.
Step
| Action
| Values
| Yes
| No
|
1
| Did you perform the Powertrain On-Board Diagnostic (OBD) System
Check ?
| --
|
Go to Step
2
| Go to
Powertrain On Board Diagnostic (OBD) System Check
|
2
| Are any of the following DTCs set?
| --
| Go to the applicable
DTC first
|
Go to Step 3
|
3
|
- Visually inspect the vacuum lines at the AIR solenoid for the
following conditions:
| • | A disconnected or damaged vacuum source. |
| • | A disconnected or damaged vacuum line to each AIR check valve. |
| • | Switched vacuum lines at the AIR solenoid. |
- If a problem is found, repair as necessary.
Did you find and correct the condition?
| --
|
Go to Step 8
|
Go to Step 4
|
4
| With the engine running, use a vacuum gauge to check for proper source
vacuum.
Is the source vacuum more than the specified value?
| 46.32 kPa
(12 in Hg)
|
Go to Step
5
|
Go to Step
6
|
5
|
- Check the vacuum lines to each AIR check valve for the following
conditions:
- If a problem is found, repair as necessary.
Did you find and correct the condition?
| --
|
Go to Step 8
|
Go to Step 7
|
6
| Locate and repair the cause of a low source vacuum to the AIR solenoid.
Is the action complete?
| --
|
Go to Step 8
| --
|
7
| Replace the AIR solenoid.
Is the action complete?
| --
|
Go to Step 8
| --
|
8
|
- Review and record the scan tool fail records information.
- Clear the DTCs.
- Operate the vehicle within the fail records conditions.
- Using the scan tool, monitor the Specific DTC Information for
DTC P0410 until the test runs.
Does the scan tool indicate that DTC P0410 failed this ignition?
| --
|
Go to Step
2
| System OK
|
