P0412

DTC P0412 (WITH RPO CODE NU3)

CIRCUIT DESCRIPTION
The secondary air injection (AIR) valve relay controls high current to the AIR control solenoid valve/pressure sensor assembly. The AIR valve relay armature is held in the open position by spring tension. Ignition voltage is supplied to the AIR valve 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 valve relay. The low side driver also incorporates a fault detection circuit, which is continuously monitored by the PCM. If the PCM detects a low side circuit fault, the driver will be turned OFF for the rest of the trip. The voltage on the control circuit should be battery voltage when the key is ON, and the AIR valve relay is at rest. If the fault detection circuit measures a low voltage under this condition, then an open or a short to ground on the control circuit or the ignition 1 voltage circuit, or an AIR valve relay coil fault may be present. If the PCM detects a low voltage on the control circuit when the AIR valve relay 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 ignition switch is in the Crank or Run position.
- The system voltage is between 9-18 volts.
- This DTC runs on a 100 ms loop.
- DTC P0412 runs continuously when the above conditions are met.

CONDITIONS FOR SETTING THE DTC
The condition exists for at least 2 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

Step 1 - Step 11:

Step 12 - Step 17:

The numbers below refer to the step numbers on the diagnostic table.
7. This step verifies that the PCM is providing ground to the AIR valve relay when the command is ON. Listen for a click when the relay operates. Be sure to command the AIR valve relay ON and the OFF. Repeat the commands as necessary.
8. This step tests if a ground is constantly being applied to the AIR valve relay.
9. This step tests for a short to voltage on the AIR valve relay control circuit. This will allow the AIR solenoid to hold the shut-off valve open continuously with the key in the OFF position.
10. This step tests for a short to ground on the AIR valve relay control circuit. This will allow the AIR valve to hold the shut-off valve open continuously with the key in the ON position.