System Diagnosis - California

AIR PUMP

TEST DESCRIPTION:

1. Remove the hose from A.I.R. Injection Manifold Check Valve prior to starting the engine. Start engine and accelerate to approximatley 1500 rpm and observe air flow from hose. If air flow increases as the engine rpm increases, the air pump is OK. If not proceed as follows:
2. Check to make sure air pump is not seized.
3. Check for proper drive belt tension.
4. Check air pump for leaking pressure relief valve. Air leakage may be heard from this valve with engine running.
5. Check hoses, tubes, and connections for proper routing and no leakage.
6. Check air injection pump for proper mounting.



CHECK VALVE

TEST DESCRIPTION:

Whenever a hose is removed from a check valve, the check valve should be inspected. Replace check valve if the hose shows signs of exhaust gas contamination. Little or no air should be felt coming from check valve with engine running at idle. Air should flow freely through the valve towards the engine cylinder head (one direction only).

Chart C-6:

Wiring Diagram for Chart C-6:

AIR MANAGEMENT CHECK (EDV VALVE)

CIRCUIT DESCRIPTION:

The Electric Diverter Valve (EDV) uses a solenoid to direct air into the exhaust ports, or to atmosphere. During cold engine starts, the ECM completes the ground circuit and the EDV solenoid is energized. Air is directed into the exhaust ports whenever the engine is started. When the vehicle is operating in "Closed Loop," or at wide open throttle, the ECM opens the circuit. This allows air to be directed to atmosphere through the divert silencer.




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

1. If the EDV does not have 10" Hg (34 kPa) of vacuum applied to the valve, inspect for pinched, plugged, or a leak in the vacuum hose. Since this is a system performance test, the vehicle will go into "Closed Loop" operation, and air will be diverted from the exhaust ports to atmosphere.
2. This test checks for a grounded Electric Divert Valve (EDV) circuit. Normally, the system light will be OFF.
3. This checks for a open circuit. Grounding the diagnostic test terminal will energize the solenoid if the ECM and/or circuit is okay. If the test light is ON, the circuit is okay, and the fault is in the valve or valve connections.

NOTE: In the preceding test, the SCAN tool is grounding each A.I.R. solenoid individually through a quad-driver circuit in the ECM. Once the test sequence is completed, clear codes and verify NO "Service Engine Soon" light exist.



DIAGNOSTIC AIDS:

This California equipped vehicle uses the same wiring harness as the Federal vehicle, but the A.I.R. Converter solenoid connector is not used. The connector is taped to the harness.