C-2D ~ Secondary Air System

Secondary Air Control VSV Circuit:

C-2D Secondary Air Control VSV Diagnostic Chart:

CIRCUIT DESCRIPTION:

The secondary air system is used to control the secondary intake valves when engine rpm is above about 5000. Using this system allows for reduced intake air at idle to improve idle quality and then opens at higher rpm to improve engine performance.

This system consists of the secondary port intake valves mounted in the lower intake manifold and a vacuum operated diaphragm which moves secondary valve linkage. The vacuum is turned ON and Off by an ECM controlled vacuum solenoid valve.

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

1. Checks to make sure there is sufficient vacuum.

2. When the ignition is ON and the engine is not running the solenoid should not be energized.

3. with the diagnostic terminal grounded, the ECM should ground WHT/BLU wire. This will energize the solenoid, allowing vacuum to pass to the diaphragm.

4. This checks the ability of the diaphragm to move the secondary intake valve linkage.

5. This step, as well as the following, checks circuit continuity.