Air Injection: Testing and Inspection

AIR Management Diagnosis:

DFI Emission Circuit:

DESCRIPTION

The AIR divert and switch solenoids are supplied with 12 volts on circuit 639 from the 10 amp number 5 solenoid fuse on the underhood relay panel. The ECM controls air management by grounding AIR switch solenoid circuit 436 and AIR divert solenoid circuit 429. To divert air to the air cleaner, the divert solenoid is de-energized. When pin C4 at the ECM is grounded, the divert solenoid energizes and diverts air to the switching valve. When the switch solenoid is de-energized the air is routed to the catalytic converter and when pin D3 at the ECM is grounded the air is routed to the exhaust ports.


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

1. With a cold engine, the air management system should switch air to the exhaust ports (the heads) to help oxidize the rich mixture that exists during cold starts and warmup.

2. With a warm engine, the air should be switched to the converter to oxidize the exhaust gas flowing to the second bed of the catalytic converter.

3. Checking for the air system to "DIVERT" air away from the converter during acceleration and deceleration. The divert function protects the converter from the following rich conditions that occur:
a. During acceleration.
b. During power enrichment.
C. When the throttle is closed to start deceleration.

4. Checking for vacuum supply to the air management valves.

5. Checking for air pump operating.

6. This branch of the tree will check for ECM ability to control air switch and air divert solenoids.

7. Checking for open or voltage to the solenoid.

8. Checking for a low resistance solenoid. If resistance is less than 20 ohms, replace the air management solenoid.