Yamaha SR400 2014 Service Manual

FUEL INJECTION SYSTEM7-38Fault code No. 43ItemFuel system voltage: the ECU is unable to monitor the batteryvoltage (an open or short circuit in the wire harness to theECU).Fail-safe system Able to start engineAble to drive vehicleDiagnostic code No. D09, D50D09FI diagnostic tooldisplayFuel system voltage (battery voltage)Approximately 12.0 VProcedureCompare the actually measured battery voltage with the FI diag-nostic tool display value. (If the actually measured battery voltageis low, charge the battery.)D50ActuationThe fuel pump relay is actuated five times at five-second intervals(2 seconds on, 3 seconds off), and the “WARNING” LED on the FIdiagnostic tool comes on each time the relay is actuated.Procedure Check that the fuel pump relay is actuated five times by listeningfor the operating sound.Probable cause of malfunction Check or maintenance job1 Connections• Fuel pump relay coupler• Fuel pump coupler• Injector coupler• Wire harness ECU coupler• Check the coupler for any pins that may bepulled out.• Check the locking condition of the coupler.• If there is a malfunction, repair it and connectthe coupler securely.2 Open or short circuit in wire harness. • Repair or replace if there is an open or shortcircuit.• Between the fuel pump relay coupler and theECUL/Y–L/Y (blue/yellow–blue/yellow)R/L–R/L (red/blue–red/blue)3 Faulty battery. • Execute diagnostic code No. D09.• Replace or recharge the battery.Refer to “CHECKING AND CHARGING THEBATTERY” on page 7-60.4 Malfunction in fuel pump relay or discon-nection• Execute diagnostic code No. D50.• Replace if defective.• If there is no malfunction with the fuel pumprelay, replace the ECU.Reinstatement method After starting, let the engine run at idle speed for about 60 sec-onds.