SHORT RUNNER VALVE (SRV)
DESCRIPTION
It is a vacuum actuated actuator attached to the
intake manifold (Fig. 13).
OPERATION
The SRV system operates under WOT conditions
above 5000 rpm to maximize engine performance.
When actuated by the PCM, the SRV solenoid ener-
gizes, allowing mechanical linkage to redirect the
intake air flow to six short runners. The PCM looks
for a current spike when actuating the solenoid. If
the spike is not present, the PCM sets the DTC.
IDLE AIR CONTROL MOTOR—PCM OUTPUT
DESCRIPTION
The idle air control motor attaches to the throttle
body (Fig. 14). It is an electric stepper motor.
OPERATION
The PCM adjusts engine idle speed through the
idle air control motor to compensate for engine load,
coolant temperature or barometric pressure changes.
The throttle body has an air bypass passage that
provides air for the engine during closed throttle idle.
The idle air control motor pintle protrudes into the
air bypass passage and regulates air flow through it.
The PCM adjusts engine idle speed by moving the
IAC motor pintle in and out of the bypass passage.
The adjustments are based on inputs the PCM
receives. The inputs are from the throttle position
sensor, crankshaft position sensor, coolant tempera-
ture sensor, MAP sensor, vehicle speed sensor and
various switch operations (brake, park/neutral, air
conditioning).
When engine rpm is above idle speed, the IAC is
used for the following functions:
• Off-idle dashpot
• Deceleration air flow control
• A/C compressor load control (also opens the pas-
sage slightly before the compressor is engaged so
that the engine rpm does not dip down when the
compressor engages)
Fig. 12 Manifold Tuning Valve
1 – MTV VALVE
Fig. 13 Short Runner Valve (SRV)
1 – INTAKE MANIFOLD
2 – SRV VALVE
Fig. 14 Idle Air Control Motor
1 – THROTTLE POSITION SENSOR
2 – IDLE AIR CONTROL MOTOR
14 - 34 FUEL SYSTEM LH
DESCRIPTION AND OPERATION (Continued)
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