2009 Suzuki 400 LTZ Quad Sport Service Manual, Page 121Get this manual
1A-57 Engine General Information and Diagnosis: Step Action 1) Connect the ECM coupler and TO sensor couplerYes No BrW, or BBr wire Loose or poor contacts on the ECM 2) Insert the needle pointed probes to the lead wire coupleropen or shorted to ground, or poor "2", coupler3) Turn the ignition switch ON"13" or "24" Open or short circuit4) Measure the voltage at the wire side coupler between connection Replace the TO BrW and BBr wires If wire and sensor with new Special tool connection are OK, oneRefer to "TO (A): 0990025008 (Multi-circuit tester set) intermittent trouble or Sensor Removal and (B): 0990025009 (Needle pointed probe set) faulty ECMInstallation in Section Recheck each 1C (Page 1C-6)"Tester knob indication terminal and wire Voltage) harness for open TO sensor voltage (Normal) circuit and poor 0.4 1.4 connection((+) terminal: BrW () terminal: BBr) Replace the ECM with known good (A) one, and inspect it againRefer to "ECM (B) Removal and Installation in Section 1C (Page 1C-2)" I933H1110058-01