Circuit Description
A fused ignition voltage is supplied to the AIR Pump Relay. The VCM controls the AIR Pump by grounding the AIR Pump Relay Control circuit. This energizes the relay and supplies voltage to the AIR Pump clutch. When the fuel system goes into Closed Loop, the VCM opens the ground to the AIR Pump Relay Control circuit.
Diagnostic Aids
An AIR Pump that is stuck on could cause a fuel trim lean code.
The AIR Shut Off Valve is spring loaded and requires air pressure to open for air to flow. A leak in the hose between the AIR Pump and the AIR Shut Off Valve could cause a no flow condition even though the pump is flowing air.
A weak or worn AIR Pump might flow air but may not be able to overcome the spring in the AIR Shut Off Valve.
An AIR supply hose that is melted before the check valve could indicate exhaust gas back-flow past the check valve.
Low AIR System volume may cause a DTC P1415, P1416 or an intermittent complaint. Also check for the following conditions:
| • | Pinched, kinked or restricted AIR pipes, hoses or fittings |
| • | Leaks, holes, loose fittings or hoses |
| • | Restricted or obstructed AIR Pump inlet hose |
| • | Worn or loose AIR Pump drive belt |
Air flowing to the exhaust ports at the wrong time can cause a false lean HO2S indication and cause the VCM to add extra fuel. This will result in increased catalytic converter temperature, because more fuel and air will be oxidizing in the converter.
The AIR System is not completely noiseless. Under normal conditions noises rises in pitch as engine speed increases.
If excessive noise is caused by the AIR system, check for the following:
| • | A seized AIR Pump |
| • | Proper mounting and bolt torque of the pump |
| • | Proper routing and connections of the hoses |
An intermittent may be caused by any of the following conditions:
| • | A poor connection |
| • | Rubbed through wire insulation |
| • | A broken wire inside the insulation |
Thoroughly check any circuitry that is suspected of causing the intermittent complaint. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.
If a repair is necessary, refer to Wiring Repairs or Connector Repairs in Wiring Systems.
Test Description
Number(s) below refer to step numbers on the Diagnostic Table
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This step will determine if the AIR System is functioning correctly.
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This step will ensure that the VCM is capable of turning the AIR Pump OFF.
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This step will determine if the VCM is capable of controlling the AIR Pump Relay.
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This step is to check for a short to voltage on the control circuit.
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This step will determine if the pump is capable of flowing air.
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This step is to check for a weak or worn AIR Pump. If the pump is weak it could flow air but may not be able to overcome the Shut Off Valve. Refer to Diagnostic Aids.
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This step is to ensure that no leaks are found in the hose between the AIR Pump and the Shut Off Valve. The Shut Off Valve is spring loaded and requires air pressure to open for air to flow. A leak could prevent the valve from opening causing a no flow condition even though the pump is flowing air.
-
An open fuse for the ignition feed circuit could be caused by a short to ground in the components operated by the relay. Also check the wiring in the circuits on the switched side of the relay. Refer to Diagnostic Aids.
Step | Action | Value(s) | Yes | No | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Step 2 | |||||||||||||
Does the Short Term Fuel Trim indicate a change of more than the specified value with 30 seconds? | 16% | Go to Step 3 | Go to Step 4 | |||||||||||||
3 | The condition is intermittent. Are any DTCs stored? | -- | Go to applicable DTC table | Go to Diagnostic Aids | ||||||||||||
4 |
Is the AIR Pump clutch engaged? | -- | Go to Step 5 | Go to Step 9 | ||||||||||||
Is the AIR Pump clutch engaged? | -- | Go to Step 6 | Go to Step 19 | |||||||||||||
6 |
Is the test lamp ON? | -- | Go to Step 7 | Go to Step 8 | ||||||||||||
7 |
Is the test lamp ON? | -- | Go to Step 30 | Go to Step 36 | ||||||||||||
8 |
Is the test lamp ON? | -- | Go to Step 31 | Go to Step 33 | ||||||||||||
9 |
Did you find a problem? | -- | Go to Step 26 | Go to Step 10 | ||||||||||||
10 |
Is the test lamp ON? | -- | Go to Step 11 | Go to Step 12 | ||||||||||||
11 |
Is the test lamp ON? | -- | Go to Step 35 | Go to Step 27 | ||||||||||||
12 |
Did you find a problem? | -- | Go to Step 26 | Go to Step 13 | ||||||||||||
13 | Check for an open in the AIR Pump clutch feed circuit between the relay and the clutch. Did you find a problem? | -- | Go to Step 26 | Go to Step 14 | ||||||||||||
14 |
Is the test lamp ON at both terminals? | -- | Go to Step 15 | Go to Step 28 | ||||||||||||
Is the test lamp ON? | -- | Go to Step 33 | Go to Step 16 | |||||||||||||
16 |
Did you find a problem? | -- | Go to Step 26 | Go to Step 17 | ||||||||||||
17 | Check for an open in the AIR Pump Relay Control circuit between the relay and the VCM. Did you find a problem? | -- | Go to Step 26 | Go to Step 18 | ||||||||||||
Is the test lamp ON? | -- | Go to Step 29 | Go to Step 36 | |||||||||||||
19 |
Does air flow from the valve? | -- | Go to Step 24 | Go to Step 20 | ||||||||||||
Does air flow from the hose? | -- | Go to Step 21 | Go to Step 23 | |||||||||||||
Does the air flow increase as the engine is accelerated? | 1500 RPM | Go to Step 22 | Go to Step 25 | |||||||||||||
Check for leaks or loose connections on the hose between the AIR Pump and the AIR Shut Off Valve. Did you find a problem? | -- | Go to Step 32 | Go to Step 34 | |||||||||||||
23 | Check for leaks or obstructions in the hose between the AIR Pump and the AIR Shut Off Valve. Did you find a problem? | -- | Go to Step 32 | Go to Step 25 | ||||||||||||
24 | Check for leaks or restrictions on the following components:
Did you find a problem? | -- | Go to Step 32 | Go to Diagnostic Aids | ||||||||||||
25 | Check for a restriction or an obstruction in the inlet hose of the AIR Pump. Did you find a problem? | -- | Go to Step 32 | Go to Step 35 | ||||||||||||
26 | Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 37 | -- | ||||||||||||
27 | Repair the open in the AIR Pump clutch ground circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 37 | -- | ||||||||||||
Repair the open or short to ground in the ignition feed circuits to the AIR Pump Relay. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 37 | -- | |||||||||||||
29 | Repair the short to voltage on the AIR Pump Relay Control circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 37 | -- | ||||||||||||
30 | Repair the short to ground in the AIR Pump Relay Control circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 37 | -- | ||||||||||||
31 | Repair the short to voltage on the AIR Pump clutch feed circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 37 | -- | ||||||||||||
32 | Repair as necessary. Refer to Secondary Air Injection Check Valve and Check Valve Pipe Replacement . Is the action complete? | -- | Go to Step 37 | -- | ||||||||||||
33 | Replace the AIR Pump Relay. Is the action complete? | -- | Go to Step 37 | -- | ||||||||||||
34 | Replace the AIR Shut Off Valve. Refer to Secondary Air Injection Check Valve and Check Valve Pipe Replacement . Is the action complete? | -- | Go to Step 37 | -- | ||||||||||||
35 | Replace the AIR Pump. Refer to Secondary Air Injection Pump Replacement . Is the action complete? | -- | Go to Step 37 | -- | ||||||||||||
36 |
Refer to Crankshaft Position System Variation Learn . Is the action complete? | -- | Go to Step 37 | -- | ||||||||||||
37 |
Does the Short Term Fuel Trim indicate a change of more than the specified value with 30 seconds? | 16% | System OK | Go to Step 4 |
