Circuit Description
A secondary air injection (AIR) pump is used on this vehicle to lower tailpipe emissions on start-up. The VCM supplies a ground to the AIR pump relay control circuit. This energizes the AIR pump relay and supplies voltage to the AIR pump clutch. The VCM uses the HO2S voltages and the short term fuel trim to diagnose the secondary air injection system.
The VCM monitors the HO2S voltages and the short term fuel trim value when the AIR pump is energized. This additional air causes the HO2S voltages to shift low, reflecting the leaner mixture. The short term fuel trim should increase above 128 confirming that the VCM is supplying additional fuel. The low HO2S voltages and higher short term fuel trim value provide confirmation that the secondary air injection system is operating properly. When the AIR pump is de-energized, the HO2S voltages should increase and begin switching normally.
This DTC is set when the VCM determines that the HO2S voltages for both banks did not respond as expected during this test. If only one HO2S responded as expected, the VCM sets either a DTC P1415 or P1416 depending on which engine bank the AIR system is inoperative.
Conditions for Running the DTC
| • | No active secondary AIR DTCs |
| • | No active CMP sensor DTCs |
| • | No active ECT sensor DTCs |
| • | No active EGR DTCs |
| • | No active fuel trim DTCs |
| • | No active IAC DTCs |
| • | No active IAT sensor DTCs |
| • | No active MAF sensor DTCs |
| • | No active MAP sensor DTCs |
| • | No active HO2S DTCs |
| • | No active transmission DTCs |
| • | No active EVAP system DTCs |
| • | No active TP sensor DTCs |
| • | No active VS sensor DTCs |
| • | No active misfire DTCs |
| • | The commanded air/fuel ratio is 14.7:1 |
| • | The system voltage is greater than 10 volts |
| • | The engine speed is greater than 550 RPM |
| • | The engine load is less than 50% |
| • | The MAF is less than 100 g/s |
| • | The system has been in closed loop operation for more than 15 seconds |
| • | The IAT is greater than 0°C (32°F) |
| • | The ECT is between 75°C and 105°C (167° to 221°F) |
Conditions for Setting the DTC
The HO2S voltage remains above 299 mV or the change in the short term fuel trim value is less than a calibrated value.
Action Taken When the DTC Sets
| • | The VCM illuminates the MIL during the second consecutive drive cycle in which the diagnostic reports a fail. |
| • | The VCM will set the DTC and records the operating conditions at the time the diagnostic fails. The VCM stores the failure information in the scan tools Freeze Frame and Failure Records. |
Conditions for Clearing the MIL or DTC
| • | The control module turns OFF the MIL after 3 consecutive drive trips when the test has run and passed. |
| • | A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles. A warm-up cycle occurs when the coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant reaches a temperature that is more than 70°C (158°F) during the same ignition cycle. |
| • | Use a scan tool in order to clear the DTCs. |
Diagnostic Aids
The secondary air injection 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 may flow air but may not be able to overcome the spring in the AIR shut-off 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 |
An AIR supply hose that is melted before the check valve could indicate exhaust gas back-flow past the check valve.
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 the step number(s) on the Diagnostic Table.
-
This step will determine if the AIR System is functioning correctly.
-
This step will determine if the VCM is capable of controlling the AIR Pump Relay.
-
This step is to check for a short to voltage on the control circuit.
-
This step will determine if the pump is capable of flowing air.
-
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.
-
This step is to ensure that no leaks are found in the hose between the AIR Pump and the AIR 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 |
Important: Before clearing DTC(s) use the scan tool to record Freeze Frame and Failure Records for reference, as data will be lost when the Clear Info function is used. 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 within 30 seconds? | 16% | Go to Step 3 | Go to Step 4 | |||||||||||||
3 | The DTC is intermittent. Are any additional DTCs stored? | -- | Go to the Applicable DTC Table | Go to Diagnostic Aids | ||||||||||||
4 |
Is the AIR Pump clutch engaged? | -- | Go to Step 15 | Go to Step 5 | ||||||||||||
5 |
Did you find a problem? | -- | Go to Step 22 | Go to Step 6 | ||||||||||||
6 |
Is the test lamp ON? | -- | Go to Step 7 | Go to Step 8 | ||||||||||||
7 |
Is the test lamp ON? | -- | Go to Step 29 | Go to Step 23 | ||||||||||||
8 |
Did you find a problem? | -- | Go to Step 22 | Go to Step 9 | ||||||||||||
9 | 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 22 | Go to Step 10 | ||||||||||||
10 |
Is the test lamp ON at both terminals? | -- | Go to Step 11 | Go to Step 24 | ||||||||||||
Is the test lamp ON? | -- | Go to Step 27 | Go to Step 12 | |||||||||||||
12 |
Did you find a problem? | -- | Go to Step 22 | Go to Step 13 | ||||||||||||
13 | 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 22 | Go to Step 14 | ||||||||||||
Is the test lamp ON? | -- | Go to Step 25 | Go to Step 30 | |||||||||||||
15 |
Does air flow from the valve? | -- | Go to Step 20 | Go to Step 16 | ||||||||||||
Does air flow from the hose? | -- | Go to Step 17 | Go to Step 19 | |||||||||||||
Does the air flow increase as the engine is accelerated? | 1500 RPM | Go to Step 18 | Go to Step 21 | |||||||||||||
Check for leaks or loose hose connections on the hose between the AIR Pump and the AIR Shut Off Valve. Did you find a problem? | -- | Go to Step 26 | Go to Step 28 | |||||||||||||
19 | 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 26 | Go to Step 21 | ||||||||||||
20 | Check for leaks or restrictions on the following components:
Did you find a problem? | -- | Go to Step 26 | Go to Diagnostic Aids | ||||||||||||
21 | Check for a restriction or an obstruction in the inlet hose of the AIR Pump. Did you find a problem? | -- | Go to Step 26 | Go to Step 29 | ||||||||||||
22 | Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 31 | -- | ||||||||||||
23 | Repair the open in the AIR Pump clutch ground circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 31 | -- | ||||||||||||
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 31 | -- | |||||||||||||
25 | 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 31 | -- | ||||||||||||
26 | Repair as necessary. Refer to Secondary Air Injection Check Valve and Check Valve Pipe Replacement . Is the action complete? | -- | Go to Step 31 | -- | ||||||||||||
27 | Replace the AIR Pump Relay. Is the action complete? | -- | Go to Step 31 | -- | ||||||||||||
28 | 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 31 | -- | ||||||||||||
29 | Replace the AIR pump. Refer to Secondary Air Injection Pump Replacement Is the action complete? | -- | Go to Step 31 | -- | ||||||||||||
30 |
Refer to Crankshaft Position System Variation Learn . Is the action complete? | -- | Go to Step 31 | -- | ||||||||||||
31 |
Does the scan tool indicate that this diagnostic Ran and Passed? | -- | Go to Step 32 | Go to Step 2 | ||||||||||||
32 | Using the scan tool, select Capture Info, Review Info. Are any DTCs displayed that have not been diagnosed? | -- | Go to the Applicable DTC Table | System OK |
