Intake Air Bypass Control Thermal Valve Test - Honda Civic 2002-2003 Service Manual

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Intake Air Bypass Control Thermal Valve Test
Special Tools
Required
Vacuum Pump/Gauge, 0-30 in. Hg A973X-041-XXXXX
1. Start the engine. Then let it idle.
NOTE: The engine coolant temperature must be
below 149 of (65 °C).
2. Remove the vacuum hose (A) from the intake air
duct, and connect a vacuum pump/gauge to the
hose.
A
A973X·041·XXXXX
I
3. Raise and lower the engine speed, and make sure
the vacuum gauge reading changes as the engine
speed changes.
If the vacuum reading does not change, check for
these problems:
• Misrouted, leaking, broken, or clogged intake air
bypass control system vacuum lines .
• A cracked or damaged intake air bypass control
thermal valve.
4. Hold the engine at 3,000 rpm with no load (in
neutral) 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 system vacuum lines.
A cracked or damaged intake air bypass control
thermal valve.
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