Air Injection: Testing and Inspection

Chart C-6 A.I.R. Managment Check (PEDES):

Wiring Diagram for Chart C-6 A.I.R. Managment Check (PEDES):

Circuit Description:
Air management is controlled by a pressure operated port valve and a converter valve, each with an ECM controlled solenoid. When the solenoid is grounded by the ECM, AIR pressure will activate the valve and allow pump air to be directed as follows:
Cold Mode - The port solenoid is energized which in turn opens the port valve and allows 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 flow past the converter valve and to the converter.
Divert Mode - Both solenoids are de-energized which opens the converter valve, allowing air to take the path of least resistance, i.e., out the divert/relief tube to atmosphere.

Test Description: Numbers below refer to circled numbers on the diagnostic chart.
1. This is a system functional check. Air is directed to ports during "Open Loop" and all engines start in "Open Loop" even on a warm engine. Since the air to the ports may be very short, prepare to observe port air prior to engine start up. This can be done by squeezing a hose.

2. This should normally 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 divert action.

3. This checks for a grounded circuit to the ECM, Test light "OFF" is normal and would indicate the circuit is not grounded.

4. 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" which indicates the problem is not in the ECM or wiring but at the solenoid connections or valve itself.

5. Checks for a grounded solenoid circuit, Test light "OFF" would indicate the circuit is normal and fault is in the valve.

*EMI