Circuit Description
The secondary air injection (AIR) solenoid relay controls high current to the AIR solenoid and shut-off valve assembly. The AIR solenoid relay armature is held in the open position by spring tension. Ignition voltage is supplied to the AIR solenoid relay coil and armature when the key is in the ON position. The powertrain control module (PCM) supplies the ground path to the relay coil control circuit 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 AIR solenoid relay. The low side driver also incorporates a fault detection circuit, which is continuously monitored by the PCM. The voltage on the control circuit should be battery voltage when the key is ON, and the AIR solenoid relay is at rest. If the fault detection circuit measures a low voltage under this condition, an indication of an open or a short to ground on the control circuit or ignition 1 voltage circuit is present. In addition, an AIR solenoid relay coil fault may be present. If the PCM detects a low voltage on the control circuit when the AIR solenoid is commanded OFF, DTC P0412 will set.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0412 Secondary Air Injection (AIR) Solenoid Relay Control Circuit
Conditions for Running the DTC
| • | The engine is running. |
| • | The system voltage is between 8-16 volts. |
| • | This DTC runs on a 100 ms loop. |
| • | DTC P0412 runs continuously once the above conditions are met. |
Conditions for Setting the DTC
The condition exists for at least 15 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.
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This step verifies that the PCM is providing ground to the AIR solenoid valve relay when the command is ON. Listen for a click when the relay operates. Be sure to command the AIR pump relay ON and the OFF. Repeat the commands as necessary.
-
This step tests if a ground is constantly being applied to the AIR solenoid relay.
-
This step tests for a short to voltage on the AIR solenoid relay control circuit. This will allow the AIR solenoid to hold the shut-off valve open continuously with the key in the OFF position.
-
This step tests for a short to ground on the AIR solenoid relay control circuit. This will allow the AIR solenoid to hold the shut-off valve open continuously with the key in the ON position.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Component Views or Engine Controls Connector End Views | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
2 | Inspect the IGN 1 fuse. Is the IGN 1 fuse open? | -- | Go to Step 6 | Go to Step 3 |
3 |
Did the DTC fail this ignition? | -- | Go to Step 4 | Go to Intermittent Conditions |
4 |
Does the test lamp illuminate on both circuits? | -- | Go to Step 5 | Go to Step 13 |
5 |
Is the resistance within the specified range? | 70-90 ohms | Go to Step 7 | Go to Step 14 |
6 |
Important: The ignition 1 voltage circuit of the AIR solenoid relay is spliced to other components of the vehicle. Test all circuits and components that are supplied by the 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 or Intermittent Conditions |
Does the test lamp turn ON and OFF with each command? | -- | Go to Step 11 | Go to Step 8 | |
Does the test lamp remain illuminated with each command? | -- | Go to Step 10 | Go to Step 9 | |
Test the AIR solenoid relay control circuit for an open or a 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 12 | |
Test the AIR solenoid relay 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 12 | |
11 | Test for a poor or an intermittent connection at the AIR solenoid relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find a condition? | -- | Go to Step 13 | Go to Step 14 |
12 | Test for shorted terminals and for poor connections 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 |
13 | Replace the underhood fuse block. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems. Did you complete the replacement? | -- | Go to Step 16 | -- |
14 | Replace the AIR solenoid relay. Refer to Relay Replacement in Wiring Systems. 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 |
Did 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 you have not diagnosed? | -- | System OK | |
