2006-2010 Suzuki DF150 / DF175 4-Stroke Outboards Service Manual, Page 70Get this manual
ENGINE CONTROL SYSTEM
TPS (Throttle Position Sensor) The TPS is installed on the throttle body and detects the degree of throttle openingThe throttle shaft is interlocked with the TPS shaftThis sensor is variable resistor changing resistance (Ohms) in accordance with the throttle openingThe varying resistance value is converted to voltage and input to the ECMBased on the TPS voltage, the ECM calculates the idle position and throttle opening and determines the control modes of various controls systems (Idle air control, VVT system control, Fuel injection control system, etcNEUTRAL SWITCH The neutral switch is installed on the throttle lever holder and used to detect the shift positionThis switch is "ON" in neutral and "OFF" in forward or reverseBased on the switch' shift position signal input, the ECM performs the following controls: When the shift is in forward or reverse at the time of engine start, no power is supplied to starter motor relay preventing starter motor engagement(Start-in-gear protectionSee page 3-45 SPS (Shift Position Sensor) The SPS is installed on the throttle lever holder and detects the shift positionThe clutch lever is interlocked with the SPS shaftThis sensor is variable resistor that changes resistance (ohms) in accordance with the shift positionThe varying resistance value is converted to voltage and input to the ECMBased on the SPS voltage, the ECM calculates and determines the change of shift position and executes the following controls When the shift is in neutral, fuel injection is controlled to prevent engine speed from exceeding 000 rmin After shifting into forward or reverse from neutral, the IAC valve is controlled to increase intake air for 0.1 second to prevent unstable engine idle or stalling