Air Injection: Testing and Inspection

Chart C-6A - Air Management Check (EDES):

Wiring Diagram for Chart C-6A - Air Management Check (EDES):

CHART C-6A - AIR MANAGEMENT CHECK (EDES)

Circuit Description:


Air Management is controlled by Air Control and Air Switching Valves, each with an ECM controlled vacuum solenoid. When the solenoid is grounded by the ECM, manifold vacuum will activate the valve and allow pump air to be directed as follows:

^ Air control solenoid not grounded by ECM - Air pump air diverted.

^ Air control solenoid grounded by ECM - Air pump air to Air Switching Valve.

^ Air switching solenoid not grounded by ECM - Air pump air to converter.

^ Air switching solenoid grounded by ECM - Air pump air to exhaust ports. Loss of vacuum would cause air to be diverted to air cleaner or atmosphere.


Test Description: Step numbers refer to step numbers on diagnostic chart.

1. This is a system functional check. Air is directed to the exhaust ports during "Open Loop". All engines start in "Open Loop", even on a warm engine. Since the air to the exhaust ports time is very short on some engines, prepare to observe port air prior to engine start-up. On some engines, this can be done by squeezing a hose. On others, steel pipes have to be disconnected.

2. This should normally set a Code 23. When any code is set, the ECM opens CKT 429 to the Air Control Valve and allows air to divert. This checks for ECM response to a fault. A grounded CKT. 429 to the ECM would prevent divert action.


3. This checks for a grounded CKT 429 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 CKT 436. Test light "OFF" would indicate the circuit is normal and fault is in the valve.