Air Injection: Testing and Inspection

Chart C-6:

CIRCUIT DESCRIPTION:

An electric air control valve solenoid directs air into the exhaust ports, or to atmosphere. Air is directed into the exhaust ports whenever the engine is started and the coolant temperature is above 20°C (68°F) and below 55°C (131°F) and the system is in "open loop" and engine speed is below 1900 rpm. When the vehicle is started and the coolant temperature is below about 20°C (68°F), the air will be diverted to the atmosphere for the entire key cycle.


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 a pinched, plugged, or a leak in the vacuum hose. The ECM should energize the EDV at idle when the coolant temperature is between 20°C (68°F) and 50°C (131°F) and system not in "closed loop." At high rpm between approximately 2000-2500 rpm, the ECM will power off the EDV which will divert air to the 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 control circuit. Grounding the diagnostic test terminal will energize the solenoid if the ECM and circuits are normal. In this step if the test light is ON, the circuits are okay, and the fault is in the valve or valve connections.



DIAGNOSTIC AIDS:

^ Removing the diverter/silencer allows for easy access to determine if air is being diverted to the atmosphere.