Purge Control Diaphragm Valve and Thermosensor
- With engine cold, there should be continuity across the terminals of thermosensor. Disconnect upper hose at purge control valve on canister. Connect a vacuum gauge to hose and start engine. No vacuum should be present.
- With engine at normal operating temperature, disconnect upper hose at purge control diaphragm valve. Connect a vacuum gauge to hose and start engine. Vacuum should appear on gauge. If not, check for voltage at purge control/unloader solenoid valve connector. Test between Black/Yellow (+) and Blue (-) wires on California models, and between Yellow (+) and ground on Federal models.
Courtesy of AMERICAN HONDA MOTOR CO., INC.