Idle Speed / Idle Air Control (IAC) Duty Inspection

WARNING: This page is about a different car, the 2004 Suzuki Vitara. However, it is still accessible from the selected car via links, so may be relevant.

Before idle speed / IAC duty check, make sure of the following.

Lead wires and hoses of engine / emission control systems are connected securely.
Accelerator cable is adjusted.
Ignition timing is within specification.
All accessories (wipers, heater, lights, A/C, etc.) are out of service.
Air cleaner has been properly installed and is in good condition.
ECM (PCM) does not detect any malfunction DTC.

After above items are all confirmed, check idle speed and IAC duty as follows.

NOTE: Before starting engine, place transmission gear shift lever in "Neutral" (shift selector lever to "P" range for A/T vehicle), and set parking brake and block drive wheels.

Connect SUZUKI scan tool to DLC with ignition switch OFF.
Special tool

(A): SUZUKI scan tool

Fig 1: Connecting Suzuki Scan Tool To DLC
Courtesy of SUZUKI OF AMERICA CORP.
Warm up engine to normal operating temperature.
Check IAC duty and idle speed by using "Data List" mode of SUZUKI scan tool.
If duty and/or idle speed is out of specifications, check idle air control system referring to "DTC P0505 / P0506 / P0507: IDLE CONTROL SYSTEM / RPM LOWER THAN EXPECTED / RPM HIGHER THAN EXPECTED: ".

Engine idle speed

Fig 2: Engine Speed Chart
Courtesy of SUZUKI OF AMERICA CORP.

IAC duty at specified idle speed

10-50%
Check that specified engine idle speed is obtained with A/C ON if vehicle is equipped with A/C. If not, check A/C ON signal circuit and idle air control system.