Intake Air Temperature (IAT) Sensor

Disconnect IAT sensor connector. Turn ignition on. Check voltage between ground and Gray/Red wire (Esteem, Vitara 1.6L and 2.0L), Light Blue wire (Grand Vitara 2.5L) or Gray wire (Swift) terminal of connector. If voltage is not 4-6 volts (4.5-5.5 on Grand Vitara), check wiring harness for an open or short. If voltage is as specified, go to next step.
Remove IAT sensor and place in container of water with a thermometer. Heat water to specified temperature and check resistance. See Fig 1. Replace IAT sensor if resistance is not within specification.

Fig 1: Identifying Intake Air Temperature Sensor Resistance (Grand Vitara & Vitara Shown; Esteem & Swift Are Similar)

Courtesy of SUZUKI OF AMERICA CORP.