Circuit Description
Voltage is supplied to the secondary air injection (AIR) solenoid by the ignition 1 voltage circuit. The powertrain control module (PCM) supplies the ground path to the solenoid by an internal integrated circuit called an output driver module (ODM). One of the ODM output circuits is configured to operate as a low side driver for the solenoid. The low side driver also incorporates a fault detection circuit, which is continuously monitored by the PCM. When the PCM completes the ground circuit to the solenoid, engine vacuum is applied to the AIR shut-off valve. If the PCM detects a low voltage on the control circuit when the solenoid is commanded OFF, or a high voltage when the solenoid is commanded ON, DTC P0412 sets.
Conditions for Running the DTC
| • | The engine speed is more than 400 RPM. |
| • | The system voltage is between 6-18 volts. |
Conditions for Setting the DTC
| • | The PCM detects that the commanded state of the driver and the actual state of the control circuit do not match. |
| • | The above conditions exist for a minimum of 5 seconds. |
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. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests for voltage to the AIR solenoid.
-
This step verifies that the PCM is providing ground to the AIR solenoid.
-
This step tests if a ground is constantly being applied to the AIR solenoid.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Controls Schematics | |||
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | |
2 | Inspect the ENG IGN 1 fuse. Is the ENG IGN 1 fuse open? | Go to Step 12 | Go to Step 3 |
3 |
Does the AIR solenoid click ON and OFF when commanded with a scan tool? | Go to Step 4 | Go to Step 5 |
4 |
Did the DTC fail this ignition? | Go to Step 5 | Go to Intermittent Conditions |
Does the test lamp illuminate? | Go to Step 6 | Go to Step 13 | |
Does the test lamp turn ON and OFF with each command? | Go to Step 10 | Go to Step 7 | |
Does the test lamp remain illuminated with each command of the scan tool? | Go to Step 9 | Go to Step 8 | |
8 | Test the AIR solenoid 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 16 | Go to Step 11 |
9 | Test the AIR solenoid 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 16 | Go to Step 15 |
10 | Test for an intermittent and for a poor connection at the AIR 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 16 | Go to Step 14 |
11 | Test for an intermittent and for a poor connection at the powertrain control module (PCM). 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 16 | Go to Step 15 |
12 |
Important: The ignition 1 voltage circuit of the AIR solenoid is spiced to other components of the vehicle. Test all circuits and components that are supplied by the ENG IGN 1 fuse for excessive current draw. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 16 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems |
13 | Repair the open in the ignition 1 voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 16 | -- |
14 | Replace the AIR solenoid. Refer to Secondary Air Injection Vacuum Control Solenoid Valve Replacement . Did you complete the replacement? | Go to Step 16 | -- |
15 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | Go to Step 16 | -- |
16 |
Does the DTC fail this ignition? | Go to Step 2 | Go to Step 17 |
17 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | System OK | |
