Component Diagnostic Charts

Chart C-6:

Chart C-6 Wiring Diagram:

CIRCUIT DESCRIPTION:

The air management system is controlled by a pressure operated port and a converter valve, each with an ECM controlled solenoid. When the solenoid is grounded by the ECM, A.I.R pump pressure will activate the valve and allow pump air to be directed as follows:

^ Cold Mode - The port (switch) solenoid is energized which in turn opens the port valve and allows air flow to the exhaust ports.

^ Warm Mode - The port solenoid is de-energized which closes the port valve and keeps the converter valve seated, thus forcing air flow past the converter valve and to the catalytic converter.

^ Divert Mode - Both solenoids are de-energized which opens the converter valve, allowing air to to take the path of least resistance which is to the atmosphere.




TEST DESCRIPTION: The numbers below refer to circled numbers on the diagnostic chart.

1. This is a system functional check. Since all engines start in open loop, air is directed into the ports. Squeeze the air hose prior to starting the engine to check port air operation.

2. This should set a code 22. When any code is set, the ECM opens the ground to the converter solenoid, and allows air to divert. This checks for ECM response to a fault. A ground in the control valve circuit to the ECM would prevent the divert action.

3. This checks for a grounded circuit to the ECM. Test light off is normal and indicates circuit is not grounded.

4. This checks for an open in the solenoid control circuits. Grounding the test terminal, should ground both solenoid circuits. Normally, the test light should be on. this indicates that the problem is not in the ECM or wiring, but at the solenoid connections or valve itself.

5. This checks for a grounded solenoid circuit. Test light off indicates that the circuit is normal, and the fault is in the valve.

NOTE: Once the test sequence is completed, clear codes and verify no "SERVICE ENGINE SOON" light exists.