Auxiliary Air Valve (Idle Speed): Testing and Inspection
Intake Air Bypass Control Thermal Valve TestSpecial Tools Required:
Vacuum pump gauge, 0 - 30 in.Hg A973X-041-XXXXX
1. Start the engine, then let it idle.
NOTE: Engine coolant temperature must be below 104 °F (40 °C).
2. Remove the vacuum hose (A) from the intake duct, and connect a vacuum gauge to the hose.
3. Raise and lower the engine speed, and make sure the vacuum gauge reading changes as the rpm changes.
If the vacuum reading does not change, check for these problems:
- Misrouted, leaking, broken, or clogged intake air bypass control thermal system vacuum lines.
- A cracked or damage intake air bypass control thermal valve.
4. Hold the engine at 3,000 rpm with no load (transmission in Park or neutral position) until the radiator fan comes on, then let it idle.
5. Raise and lower the engine speed, and make sure the vacuum gauge reading does not change as the rpm changes.
If the vacuum reading changes, check for these problems:
- Misrouted, leaking, broken, or clogged intake air bypass control thermal system.
- A cracked or damaged intake air bypass control thermal valve.