Circuit Description
The secondary air injection (AIR) pump used on this vehicle lower tail pipe emissions during start-up. The AIR system consists of the following items:
| • | The AIR pump |
| • | The shut-off valves |
| • | The vacuum control solenoid valve |
| • | The system hoses and piping |
| • | 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 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 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 quickly reach normal working temperature, thus lowering the tail pipe emissions on a start-up. The PCM tests the AIR system for the following conditions:
| • | AIR system (overall system including both banks, and results in DTC P0410). |
| • | AIR system bank 1 (DTC P1415) |
| • | AIR system bank 2 (DTC P1416) |
| • | AIR relay (DTC P0418) |
| • | AIR vacuum control solenoid (DTC P0412) |
The PCM runs two tests to diagnose the AIR system, Passive, and Active. Both tests involve a response from the fuel control heated oxygen sensors (HO2S) , (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, the DTC 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 mass air flow (MAF) is less than 35 g/s. |
| • | The air/fuel ratio is more than 12.5:1. |
| • | The engine coolant temperature (ECT) is between 5-110°C (41-230°F). |
| • | The intake air temperature (IAT) is between 5-60°C (41-140°F). |
| • | The power enrichment, or deceleration fuel cut-off (DFCO) 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 evaporative emission (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 pump, the HO2S voltage for both fuel control sensors is above 250 mV for 20 seconds (200 mV for 7 seconds on a hot start). |
| • | When the AIR pump is turned OFF, the HO2S voltage for both fuel control sensors is below 740 mV for 20 seconds (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 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
Notice: Use the connector test adapter kit J 35616-A for any test that
requires probing the following items:
• The PCM harness connectors • The electrical center fuse/relay cavities • The component terminals • The component harness connector
Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may assist in diagnosing the condition. The information may help determine how often the condition that set the DTC occurs.
Step | Action | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | |||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | |||||||
2 | Is the AIR pump fuse OK? | Go to Step 3 | Go to Step 14 | ||||||
3 | Did DTC P0412 or DTC P0418 also set? | Go to Step 4 | |||||||
4 |
Does the AIR pump turn ON? | Go to Step 9 | Go to Step 5 | ||||||
5 |
Important: Refer to Electrical Center Identification Views in Wiring Systems for relay terminal identification.
Is the test lamp illuminated? | Go to Step 6 | Go to Step 16 | ||||||
6 | Jumper the B+ terminal to the AIR pump feed circuit at the relay harness connector using a fused jumper wire. Refer to Using Fused Jumper Wires in Wiring Systems. Does the AIR pump turn ON? | Go to Step 22 | Go to Step 7 | ||||||
7 |
Is the test lamp illuminated? | Go to Step 8 | Go to Step 17 | ||||||
8 |
Is the test lamp illuminated? | Go to Step 24 | Go to Step 18 | ||||||
9 |
Is an engine vacuum displayed on the vacuum gauge? | Go to Step 10 | Go to Step 21 | ||||||
10 |
Is an engine vacuum indicated on the vacuum gauge when the AIR system is enabled? | Go to Step 11 | Go to Step 23 | ||||||
11 | Inspect the vacuum lines to each AIR shut-off valve for the following conditions:
Did you find and correct the condition? | Go to Step 26 | Go to Step 12 | ||||||
12 |
Is air present at both hoses? | Go to Intermittent Conditions | Go to Step 13 | ||||||
13 |
Did you find and correct the condition? | Go to Step 26 | Go to Intermittent Conditions | ||||||
14 |
Does the test lamp illuminate? | Go to Step 19 | Go to Step 15 | ||||||
15 |
Does the test lamp illuminate? | Go to Step 20 | Go to Step 25 | ||||||
16 | Repair the open circuit between the fuse and the relay. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | Go to Step 26 | -- | ||||||
17 | Repair the open circuit between the AIR pump and the AIR relay. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | Go to Step 26 | -- | ||||||
18 | Repair the poor ground connection or the open ground circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | Go to Step 26 | -- | ||||||
19 | Repair the short to ground in the relay B+ supply circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | Go to Step 26 | -- | ||||||
20 |
Is the action complete? | Go to Step 26 | -- | ||||||
21 | Repair the vacuum hose as necessary. Is the action complete? | Go to Step 26 | -- | ||||||
22 | Replace the AIR pump relay. Is the action complete? | Go to Step 26 | -- | ||||||
23 | Replace the AIR solenoid valve. Refer to Secondary Air Injection Vacuum Control Solenoid Valve Replacement . Is the action complete? | Go to Step 26 | -- | ||||||
24 |
Did you find and correct the condition? | Go to Step 26 | Go to Step 25 | ||||||
25 | Replace the AIR pump. Refer to Secondary Air Injection Pump Replacement . Is the action complete? | Go to Step 26 | -- | ||||||
26 |
Does the DTC run and pass? | Go to Step 27 | Go to Step 2 | ||||||
27 | Select the Capture Info option and the Review Info option using the scan tool. Are any DTCs displayed that you have not diagnosed? | System OK | |||||||
