A8 Quattro Sedan V8-4.2L (ABZ) (1998)
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Idle Air Control Valve: Testing and Inspection
Idle Air Control (IAC) Valve, Checking
Idle Air Control (IAC) Valve, Checking
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Remove IAC valve -N71- from mounting on engine (do not disconnect harness connector).
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Visually inspect rotary valve for scuff marks (arrow).
CAUTION!
Do not use a screwdriver or other tools to check the valve for ease of movement.
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Initiate output Diagnostic Test Mode (DTM) and check actuation of IAC valve. Refer "Scan Tool Testing/Output Diagnostic Test Mode (DTM),
(Function 03)" See: Computers and Control Systems/Testing and Inspection
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Check that rotary slide moves freely between fully open and fully closed positions.
If there are scuff marks or other malfunctions that restrict free movement of rotary slide:
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Replace IAC valve.
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Check Diagnostic Trouble Code (DTC) memory.
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Generate readiness code. Refer "Monitors, Trips and/or Drive Cycle (Readiness Code)/Generating, Readiness Code" See: Computers and Control
Systems/Testing and Inspection
If valve does not respond:
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Check idle air control signal from ECM. See: Idle Air Control (IAC) Valve, Electrical Testing