Description
The control module activates the secondary air injection (AIR) system by grounding both the pump relay and the vacuum control solenoid control circuits. This energizes the pump and the vacuum control solenoid. Vacuum is then applied, opening the shut-off valves. The pump then forces filtered fresh air into the exhaust stream in order to accelerate catalyst operation. The control module will run up to three diagnostic tests using the pre-catalyst heated oxygen sensor (HO2S) voltage and short term FT to diagnose the system. The control module can activate the system specifically for diagnostic purposes. If the system is operating properly, the HO2S voltage will decrease and the short term FT will increase when the system is activated. If a system air flow problem is detected, this diagnostic trouble code (DTC) will set. When inactive, the system prevents air flow in either direction.
Conditions for Running the DTC
| • | DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121-P0123, P0125, P0131-P0135, P0137, P0138, P0140, P0141, P0171, P0172, P0300, P0440, P0442, P0446, P0506, P0507, P1133, P1134, or P1441 are not set. |
| • | The engine coolant temperature (ECT) is between 4°C (39°F) and 110°C (230°F). |
| • | The start-up ECT is below 70°C (158°F). |
| • | The engine operates for more than 25 seconds. |
| • | The intake air temperature (IAT) is between 4°C (39°F) and 70°C (158°F). |
| • | The short term FT is between -3 and +4. |
| • | The engine load is between 24-40 percent. |
| • | The barometric pressure (BARO) is above 75 kPa. |
| • | The mass air flow (MAF) is between 11-19.5 grams per second. |
| • | The engine speed is more than 1,200 RPM. |
| • | The ignition voltage is between 10-18 volts. |
| • | The vehicle speed is more than 8 km/h (5 mph). |
Conditions for Setting the DTC
| • | The pre-catalyst HO2S voltage remains above a predetermined lean value during the test. |
| AND |
| • | The Short Term FT does not increase a calibrated amount during the test. |
| • | Both conditions above exist for 2 consecutive 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
| • | Low system airflow can cause an intermittent complaint. Inspect for the following conditions: |
| - | Any restriction in the exhaust system that may produce back pressure |
| - | Pinched, kinked, restricted, or leaking pipes, hoses, or fittings |
| - | A restricted pump inlet hose, duct, or filter |
| - | Pinched, kinked, restricted, or leaking vacuum lines |
| - | Heat damage |
| • | A short to voltage in the pump relay control circuit can result in the AIR pump running continuously with the ignition OFF by back-feeding to ground. This will eventually result in pump failure. |
| • | An AIR pump that had become inoperative and had shown indications of having exhaust gases in the outlet port would indicate check valve failure. |
| Notice: Do not operate the AIR pump for more than 60 seconds. Continuous operation of the AIR pump in excess of 60 seconds will damage the AIR pump. |
| • | If the DTC cannot be duplicated and is determined to be intermittent, reviewing the Failure Records data can be useful in determining when the DTC was last set. Also refer to Intermittent Conditions . |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Other secondary air injection DTCs should be diagnosed first if set. If the HO2S voltage remains below 50 mV for approximately 5 seconds, the system is operating normally.
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Listen for a running motor. Command both the ON and OFF states. Repeat the commands as necessary.
-
Listen for a click when the device operates. Command both ON and OFF states. Repeat the commands as necessary.
-
This step begins to eliminate an airflow problem.
-
This step tests for a vacuum leak at the valve.
-
This step tests the operation of the valve.
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This step tests the control circuit for operation.
-
This step bypasses the relay to test pump operation.
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This step tests the control circuit for operation.
-
This step eliminates the relay and the control circuit as a cause for continuous pump operation.
-
This step tests the control circuit for operation.
-
The pump may have failed from another fault. If the pump operates without a command, refer to step 18.
-
If the HO2S voltage remains below 50 mV for approximately 5 seconds, the system is operating normally.
Step | Action | Values | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |||||||||
|
Important: If DTC P0412 or P0418 are also set, refer to applicable DTC first.
Does the scan tool indicate pre-catalyst HO2S voltages are below the specified value for the duration of system operation? | 50 mV | Go to Diagnostic Aids | Go to Step 3 | |||||||||
3 |
Important: If heat damage is indicated, replace the shut-off valve on the bank that the damage is present. Visually inspect for the following:
Did you find and correct the condition? | -- | Go to Step 42 | Go to Step 4 | ||||||||
Does the pump turn ON and OFF with each command? | -- | Go to Step 5 | Go to Step 11 | |||||||||
Use a scan tool in order to command the AIR solenoid ON and OFF. Does the solenoid turn ON and OFF with each command? | -- | Go to Step 6 | Go to Step 14 | |||||||||
Is airflow present at both hoses? | -- | Go to Step 7 | Go to Step 16 | |||||||||
7 |
Does the vacuum measure above the specified value? | 33 kPa (10 in Hg) | Go to Step 8 | Go to Step 33 | ||||||||
8 |
Important: Perform this step at each valve.
Does the vacuum measure above the specified value at both lines when the solenoid is commanded ON? | 33 kPa (10 in Hg) | Go to Step 9 | Go to Step 26 | ||||||||
|
Important: Perform this step at each valve.
Does the valve hold vacuum for 1 minute? | -- | Go to Step 10 | Go to Step 37 | |||||||||
|
Important: Perform this step at each valve.
Can you blow freely through the valve? | -- | Go to Step 27 | Go to Step 37 | |||||||||
11 |
Does the test lamp illuminate when probing both circuits? | -- | Go to Step 12 | Go to Step 22 | ||||||||
Does the test lamp turn ON and OFF with each command? | -- | Go to Step 13 | Go to Step 17 | |||||||||
Does the pump operate? | -- | Go to Step 28 | Go to Step 20 | |||||||||
14 |
Does the test lamp illuminate? | -- | Go to Step 15 | Go to Step 23 | ||||||||
Does the test lamp turn ON and OFF with each command? | -- | Go to Step 29 | Go to Step 17 | |||||||||
16 |
Is airflow present at the pump outlet? | -- | Go to Step 36 | Go to Step 40 | ||||||||
17 | Does the test lamp remain illuminated with each command? | -- | Go to Step 24 | Go to Step 25 | ||||||||
Does the pump stop operating? | -- | Go to Step 19 | Go to Step 32 | |||||||||
Does the test lamp turn ON and OFF with each command? | -- | Go to Step 38 | Go to Step 24 | |||||||||
20 |
Does the test lamp illuminate? | -- | Go to Step 30 | Go to Step 21 | ||||||||
21 |
Does the test lamp illuminate? | -- | Go to Step 35 | Go to Step 34 | ||||||||
22 | Test the applicable feed circuit for the following conditions:
Did you find and correct the condition? | -- | Go to Step 42 | Go to Step 40 | ||||||||
23 | Test the solenoid feed circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 42 | Go to Step 39 | ||||||||
24 | Test the control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 42 | Go to Step 41 | ||||||||
25 |
Important: If diagnosis reveals a short to voltage in the AIR pump relay control circuit, check the AIR pumps. Refer to Diagnostic Aids. Test the control circuit for an open or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 42 | Go to Step 31 | ||||||||
26 | Inspect the vacuum line for a leak or for a restriction. Did you find and correct the condition? | -- | Go to Step 42 | Go to Step 39 | ||||||||
27 | Inspect for a leaking or restricted AIR pipe/hose between the shut-off valve and the exhaust. Did you find and correct the condition? | -- | Go to Step 42 | Go to Restricted Exhaust in Engine Exhaust | ||||||||
28 | Test for poor connections at the relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 42 | Go to Step 38 | ||||||||
29 | Test for poor connections at the solenoid. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 42 | Go to Step 39 | ||||||||
30 | Test for poor connections at the pump. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 42 | Go to Step 40 | ||||||||
31 | Test for poor connections at the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 42 | Go to Step 41 | ||||||||
32 | Repair the short to voltage in the pump feed circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 42 | -- | ||||||||
33 | Repair the vacuum source. Did you complete the repair? | -- | Go to Step 42 | -- | ||||||||
34 | Repair the open feed circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 42 | -- | ||||||||
35 | Repair the open ground circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 42 | -- | ||||||||
36 | Repair the AIR pipe/hose for a leak or a restriction between the pump and the shut-off valve. Did you complete the repair? | -- | Go to Step 42 | -- | ||||||||
37 | Replace the shut-off valve. Refer to Secondary Air Injection Shutoff Valve Replacement - Bank 1 or Secondary Air Injection Shutoff Valve Replacement - Bank 2 . Did you complete the replacement? | -- | Go to Step 42 | -- | ||||||||
38 | Replace the relay. Did you complete the replacement? | -- | Go to Step 42 | -- | ||||||||
39 | Replace the solenoid. Refer to Secondary Air Injection Vacuum Control Solenoid Valve Replacement . Did you complete the replacement? | -- | Go to Step 42 | -- | ||||||||
Does the replacement AIR pump run continuously? | -- | Go to Step 18 | Go to Step 42 | |||||||||
41 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 42 | -- | ||||||||
Does the scan tool indicate pre-catalyst HO2S voltages are below the specified value for the duration of system operation? | 50 mV | Go to Step 43 | Go to Step 3 | |||||||||
43 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |||||||||
