Intake Air By-Pass Control Thermal Valve Test (Odyssey)
- Start engine and allow to idle. Ensure engine coolant temperature is below 104°F (40°C). Disconnect vacuum hose located between air intake duct and intake air by-pass control thermal valve. See Fig 1. Connect vacuum pump/gauge to open end of hose. Raise and lower engine RPM. Ensure vacuum gauge reading changes as RPM changes. If vacuum reading does not change, check for misrouted, leaking, broken or clogged intake air by-pass control thermal system vacuum lines. If vacuum reading does change, go to next step. If vacuum lines are okay, check for cracked or damaged intake air by-pass control thermal valve.
- Hold engine speed at 3000 RPM under no load with transmission in Park or Neutral until radiator fan comes on. Allow engine to idle. Raise and lower engine RPM. Ensure vacuum gauge reading does not change as RPM changes. If vacuum reading changes, check for misrouted, leaking, broken or clogged intake air by-pass control thermal system vacuum lines. If vacuum lines are okay, check for cracked or damaged intake air by-pass control thermal valve.
Courtesy of AMERICAN HONDA MOTOR CO., INC.