2009 Suzuki 400 LTZ Quad Sport Service Manual, Page 110Get this manual
Engine General Information and Diagnosis: Step Action 1) Turn the ignition switch OFFYes GB, or BBr wire open or shorted to 2) Remove the IAP sensorRefer to "IAP Sensor Removal ground, or poor "6", and Installation in Section 1C (Page 1C-2)""13" or "24" 3) Connect the vacuum pump gauge to the vacuum port of connectionthe IAP sensorArrange new 1.5 batteries in series (1) (check that If wire and connection are OK, total voltage is 4.5 5.5 V) and connect () terminal to intermittent trouble or the ground terminal "B" and (+) terminal to the VCC faulty ECMterminal "A"4) Check the voltage between Vout "C" and groundAlso, Recheck each terminal and wire check if voltage reduces when vacuum is applied up to harness for open 400 mmHg by using vacuum pump gaugecircuit and poor Special tool connection(A): 0991747011 (Vacuum pump gauge) Replace the ECM (B): 0990025008 (Multi-circuit tester set) with known good Tester knob indication one, and inspect it Voltage) againRefer to "ECM Removal and Installation in Section "B" 1C (Page 1C-2)"(A) "C"