P0410

Engine Controls Schematics: Air Pump Motor And Vacuum Valve Solenoid, NC8 (Calif. Systems Emissions, ULEV) Only:

DESCRIPTION

The control module activates the Secondary Air Injection System by grounding both the pump relay and the vacuum control solenoid control circuits simultaneously. This energizes the pump and the vacuum control solenoid. Vacuum is then applied, opening the valves. The pump then forces fresh air into the exhaust stream in order to accelerate catalyst operation. The control module will run up to 3 diagnostic tests using the pre-catalyst HO2S voltage and Short Term FT to diagnose the system. The system can be diagnosed during normal Secondary Air Injection operation or the control module can activate the system specifically for diagnostic purposes. If an air flow problem is detected this DTC will set. When inactive, the system prevents air flow in either direction.

CONDITIONS FOR RUNNING THE DTC
^ No EVAP, ECT, Fuel Trim, Idle Control, HO2S, MAF, IAT, TP or Misfire DTCs set.
^ The engine run time is more than 90 seconds.
^ The fuel control is in closed loop.
^ The engine coolant temperature is between 65°C and 110°C (149°F - 230°F).
^ The Mass Air Flow (MAF) is less than 8.1 g/s.
^ The ignition voltage is more than 11 volts.
^ The engine speed is more than 850 RPM.
^ The fuel system is operating in DECEL control cell.

CONDITIONS FOR SETTING THE DTC
^ The pre-catalyst HO2S voltage remains above a predetermined lean value during the test.
AND
^ The Short Term FT does not increase a calibrated amount during the test.
^ Both conditions above exist for 3 consecutive tests.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will illuminate the Malfunction Indicator Lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
^ The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.
^ If the misfire is determined to be catalyst damaging, the PCM will flash the MIL.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been run and passed.
^ The History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using a scan tool.

DIAGNOSTIC AIDS

NOTE: Refer to Test Probe Notice in Service Precautions.

If the problem is intermittent, refer to Symptoms. Symptom Related Diagnostic Procedures

If the DTC cannot be duplicated and is determined to be intermittent, reviewing the Failure Records can be useful in determining when the DTC was last set. Also refer to Testing for Intermittent and Poor Connections in Diagrams.


TEST DESCRIPTION

Steps 1 - 13:

Steps 16 - 26:

Steps 29 - 42:

The numbers below refer to the step numbers on the diagnostic table.
41. The replacement PCM must be programmed.