Mass Air Flow (MAF) and Intake Air Temperature (IAT) Sensor On-Vehicle Inspection

NOTE: Use voltmeter with high-impedance (10 kohm/V minimum) or digital type voltmeter.

Remove ECM, referring to ENGINE CONTROL MODULE (ECM) REMOVAL AND INSTALLATION .
Connect couplers to ECM.
Disconnect coupler (1) from MAF and IAT sensor.
Connect voltmeter to "BLK/RED" wire terminal (3) of MAF and IAT sensor coupler (1) disconnected and ground (2).
Turn ignition switch ON and check that voltage is battery voltage.
If not, check if wire harness is open or connection is poor.

Fig 1: Connecting Voltmeter To " BLK/RED " Wire Terminal Of MAF And IAT Sensor Coupler Disconnected And Ground
Courtesy of SUZUKI OF AMERICA CORP.
Turn ignition switch OFF and connect MAF and IAT sensor coupler to MAF and IAT sensor.
Turn ignition switch ON and check voltage at "C46-29" terminal.
"Standard" voltage between "C46-29" terminal and ground

0.5 - 1.0 V

Fig 2: Checking Voltage Between C46-29 Terminal And Ground
Courtesy of SUZUKI OF AMERICA CORP.
Start engine and check that voltage is lower than 5 V and it rises as engine speed increases.
Reference voltage

1.3 - 1.8 V at specified idle speed
If check result is not as specified, cause may lie in wire harness, coupler connection, MAF and IAT sensor or ECM.