Air Injection: Testing and Inspection

Fig. 026 - WIRING DIAGRAM for Chart C-6 Air Management Check (1 of 2). VIN 8:

CHART C-6, AIR MANAGEMENT CHECK

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:
a. Air control solenoid not grounded by ECM - Air diverted to silencer.
b. Air control solenoid grounded by ECM - Air to Air Switching Valve.
c. Air switching solenoid not grounded by ECM - Air to converter.
d. Air switching solenoid grounded by ECM - Air to exhaust ports.

Fig. 025 - Chart C-6 Air Management Check (1 of 2).:

1. This is a system functional check. Engine coolant temperature must be below 60°C (150°F). This step checks for air switching from port to converter. Since the air to port time is very short on some engines, prepare to check for air to ports immediately after engine starts.
2. This will set a Code 42. When a code is set, the ECM opens the ground to the Air Control Valve and allows air to divert. This checks for ECM response to a system fault.
3. This checks for a grounded circuit to the ECM. Test light "OFF" is normal and would indicate the circuit is not grounded.
4. Solenoids are turned "ON" or "OFF" by the ECM internal electronic switches called "drivers". Each driver is part of a group of four called "Quad-Drivers". Failure of one can damage any other driver within the set.
Solenoid coil resistance must measure more than 20 ohms. Less resistance will cause early failure of the ECM "DRIVER". Using an ohmmeter, check the solenoid coil resistance of all ECM controlled relays and solenoids. See ECM wiring diagrams for coils to check and pin identification.

Fig. 026 - WIRING DIAGRAM for Chart C-6 Air Management Check (1 of 2). VIN 8:

Fig. 027 - Chart C-6A Air Management Check (2 of 2).:

CHART C-6A, AIR MANAGEMENT CHECK

5. 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.
6. Checks for a grounded switching valve circuit. Test light "OFF" would indicate the circuit is normal and fault is in the valve.
7. Solenoids are turned "ON" or "OFF" by the ECM internal electronic switches called "drivers". Each driver is part of a group of four called "Quad-Drivers". Failure of one can damage any other driver within the set.

Solenoid coil resistance must measure more than 20 ohms. Less resistance will cause early failure of the ECM "DRIVER". Using an ohmmeter, check the solenoid coil resistance ECM controlled relays and solenoids. See ECM wiring diagrams for coils to check and for pin identification.