23 MINIMUM DRIVE PULSE (MDP) LEARNING When the pulse value that the injector starts injection is measured, it is called mininum drive pulse (MDP). Through MDP controls, can correct pilot injections effectively. Pilot injection volume is very small, 1 ~ 2 mm/str, so precise control of the injector can be difficult if it gets old. So there needs MDP learning to control the very small volume precisely through learning according to getting older injectors. Learning Conditions Coolant temperature Vehicle speed Intake manifold pressure Engine speed Battery voltage Fuel temperature Initial MDP learning on each injector P1171 P1172 P1173 P1174 P1175 Trouble Codes Trouble code Description Fault MDP learning on injector No. 1 Fault MDP learning on injector No. 2 Fault MDP learning on injector No. 3 Fault MDP learning on injector No. 4 Fault MDP learning on injector No. 5 > 75 C > 50 Km/h (over 5 seconds) > 0.7 bar > 2,500 rpm 10 V < MDP < 16 V 0 < fuel temperature < 80 C 5 seconds Diagnosis Check each injector SENSOR CONTROL FUEL COOLING LUB EXHAUST INTAKE HOUSING ASSY GENERAL
24 08 Accelerator Pedal Sensor <Location of Accelerator Pedal Sensor> <When Depressing the Accelerator Pedal and Brake Pedal Simultaneously> Accelerator pedal sensor changes accelerator pedal position into electrical signal and then sends to ECU to let know the driver s demand. There are 2 sensors in the accelerator pedal sensor. Accelerator pedal No.1 (ACC 1) sensor signal determines fuel injection volume and injection timing during driving, and accelerator pedal No. 2 (ACC 2) sensor signal compares whether the No. 1 sensor signal value is correct. If accelerator pedal No. 1 and 2 sensors are defective, ECU remembers defect code, and acceleration responses are getting bad and engine rpm hardly increases. NOTICE When depressing the accelerator pedal and brake pedal simultaneously while driving, the acceleration response will be diminished abruptly and cannot drive with over 70 km/h even though depressing the accelerator pedal to its end. At this time, the trouble code of P-1124 Accelerator pedal sensor stuck is stored into ECU. If depressing the accelerator pedal over 3 times, it will be resumed to normal condition. For detailed information, refer to Diagnosis section in this manual. 2 4 Signal 1 A/PEDAL SENSOR 3 1 6 Signal 2 5
25 Coolant Temperature Sensor GENERAL <Coolant Temperature Sensor> <Output Characteristics of Coolant Temperature Sensor> Coolant temperature sensor is a NTC resister that sends coolant temperature to ECU. NTC resister has characteristics that if the engine temperature rises, the resistance lowers so the ECU detects lowering signal voltages. If the fuel injected into the engine through injector has more turbulence, then combusts very well. However, if engine temperature is too low, the fuel injected as foggy state forms big compounds causing incomplete combustion. So the sensor detects coolant temperature and changes coolant temperature changes into voltage then sends to ECU to increase the fuel volume during cold start for better starting. And detects engine overheating for fuel volume reduction to protect the engine. ECU functions as below with coolant temperature sensor signals. 1. When engine is cold, controls fuel volume to correct idle speed. 2. When engine is overheated, controls electrical fan and A/C compressor to protect the engine. 3. Sends information for emission control. Temperature ( C) 20 50 80 120 NTC 1 Resistance (Ω) 2,449 826 321 123 Temp. NTC 2 Resistance (Ω) 6,062 1,800 638 200 Resistance SENSOR CONTROL FUEL COOLING LUB EXHAUST INTAKE HOUSING ASSY Signal Auto amp <Circuit Diagram of Coolant Temperature Sensor>
26 08 Boost Pressure Sensor D20DT D27DT Not using terminals <Boost Pressure Sensor> <Location of Boost Pressure Sensor> Boost pressure sensor uses piezo element and uses only 3 terminals out of 6. It sets fuel injection timing and corrects fuel injection volume according to atmospheric pressure. The other function is determining EGR operation stops. 1. Output voltage calculation VO =VS x ( P x 0.004-0.04) VO : Output voltage VS : Supply voltage P : Applying voltage Voltage (V) Pressure (bar) <Output Characteristics of Sensor>
27 Performance proofing pressure range Performance proofing temperature range 20 ~ 250 KPa - 40 ~ 110 C GENERAL Storage proofing temperature range Performance proofing supply voltage Max. consuming current Responsibility Tightening torque - 40 ~ 125 C 4.85 ~ 5.35 V 10 ma (supply voltage at 5.35 V) REF 5V SIG <Circuit Diagram of Booster Pressure Sensor> TR 7ms 10 Nm SENSOR CONTROL FUEL COOLING LUB EXHAUST INTAKE HOUSING ASSY
28 08 Vehicle Speed Sensor The ABS or ESP control unit sends the vehicle speed signals to ECU. ECU uses these signals to calculate the vehicle speed and meter cluster shows signals as vehicle speed. Function 1. Limits idle control correction duty range 2. Controls cooling fan 3. Cuts fuel injection if exceeds max. speed 4. Controls vehicle shifting feeling 5. Used for exhaust gas control mode ABS or ESP control unit CAN communication <Circuit Diagram of Vehicle Speed Sensor> Barometric Sensor It is built-in the ECU and detects absolute pressure of atmosphere to correct fuel injection timing and injection volume according to altitude.
29 Other switches Brake switch Brake switch detects brake pedal operations and then sends to engine ECU. It has dual structure with 2 combined switches and there are brake switch 1 and 2. When these 2 signals are input, engine ECU recognizes as normal brake signals. These switch signals are related with accelerator pedal sensor operations and used to control the fuel volume during braking. It means there are no problems in operating accelerator pedal when the brake pedal is operated but the fuel volume reduces if operates brake pedal while the accelerator pedal is depressed. IGN 1 Clutch pedal switch <Brake Switch Circuit> Clutch pedal switch is installed on the upper of the clutch and sends clutch pedal operations to engine ECU. Contact type switch allows engine ECU to recognize the shifting points to correct the fuel volume. It means it corrects fluctuation happens during gear shifting. Another different function is canceling auto cruise function if equipped (auto cruise control - equipped for export). Engine ground Brake pedal switch (NC) Brake lamp switch (NO) Clutch pedal switch (NO) 2 1 SENSOR CONTROL FUEL COOLING LUB EXHAUST INTAKE HOUSING ASSY GENERAL <Clutch Pedal Switch Circuit>