P0412

Schematic:

CIRCUIT DESCRIPTION
The PCM controls the relay by grounding the control circuit via an internal switch called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver has a fault line which the PCM monitors. When the PCM commands a component ON, the voltage of the control circuit should be low (near 0 volts). When the PCM commands the control circuit to a component OFF, the voltage potential of the circuit should be high (near the battery voltage). If the fault detection circuit senses a voltage other than what is expected, the fault line status changes causing the DTC to set.

CONDITIONS FOR RUNNING THE DTC
^ The engine speed is more than 400 RPM.
^ The ignition voltage is between 6.0 volts and 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.
^ All the above conditions are present for a minimum of 5 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
^ The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
^ A last test failed (current DTC) clears when the diagnostic runs and does not fail.
^ A History DTC clears after 40 consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.
^ Use a scan tool in order to clear the MIL/DTC.

DIAGNOSTIC AIDS

IMPORTANT:
^ Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing/replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM.
^ For any test that requires probing the PCM or a component harness connector, use the J35616-A connector test adapter kit. Using this kit prevents damage to the harness/component terminals. Refer to Using Connector Test Adapters in Diagrams.
^ The scan tool offers three modes of AIR output controls. AIR pump relay, AIR solenoid, and AIR system.
^ For underhood fuseblock terminal identification, refer to Electrical Center Identification Views in Diagrams.
^ For an intermittent, refer to Symptoms. Symptom Related Diagnostic Procedures

TEST DESCRIPTION

Steps 1 - 6:

Steps 7 - 16:

The numbers below refer to the step numbers on the diagnostic table.
3. Listen for an audible click when the solenoid valve operates. Be sure that both the ON and the OFF states are commanded. Repeat the commands as necessary.
5. Tests for voltage to the AIR solenoid valve.
6. Verifies that the PCM is providing ground to the AIR solenoid valve.
7. Tests if a ground is constantly being applied to the AIR solenoid valve.