Initial Inspection and Diagnostic Overview

AIR ECT Valve Chart:

AIR ECT Valve Circuit:

Circuit Description:
An electric AIR control valve solenoid directs air into the exhaust ports or the air cleaner. During cold start the control module completes the ground circuit, the solenoid is energized, and air is directed to the exhaust ports. As the system goes to "Closed Loop," the control module opens the ground circuit, the solenoid is de-energized, and air goes to the air cleaner.

Chart Test Description: Number(s) below refer to circled number(s) on the diagnostic chart.

1. This is a system performance test, to be performed if a malfunction is suspected or observed. When the vehicle goes to "Closed Loop," air will switch from the ports and divert to the air cleaner. (Under normal, steady-state condition, and vehicle not at idle.)

2. Tests for a grounded electric divert circuit. Normal system light will be "OFF."

3. Checks for an open control circuit. Grounding diagnostic terminal will energize the solenoid, if control module and circuits are normal. In this step, if test light is "ON," circuits are normal and fault is in valve connections or valve.

4. Checks for voltage from battery through a fuse to the solenoid.