ECT sensor
Ohmmeter
Examination:
1. Drain the engine coolant and detach the water temperature sensor (See Fig. 266).
2. As shown in Fig. 267, place the water temperature sensor into a water container and heat it. Use a multimeter to
measure the resistance that varies with the water temperature; it should fall into the allowable range as shown in Fig. 268.
If not so, you shall replace the water temperature sensor.
3. Reinstall the water temperature sensor with a new washer, and then fill the engine coolant into the radiator.
4. Switch off the ignition and remove the ECU plug. Switch on the ignition and measure the voltage between THW and E2
(See Fig. 269); When the water temperature is 20°C, the voltage should range from 0.5V to 3.4V; when the water tempera-
ture is 80°C, the vo ltage should range from 0.2V to 1.0V.
Fig. 266 Detach the ECT (Engine Coolant Temperature) sensor
Fig. 268 The allowable resistance range for water temperature sensor
Fig.267 Measure the resistance of the water temperature sensor
Fig. 269 The voltage check circuit for THW-E2
Simple measurement method:
Temperature sensor:(Removing the joint) place the multimeter at ohm gear, and connect 2 terminals respectively to 1# pin
and 2# pin of sensor, and rated resistance at 20
o
C is 2.5kΩ±5%, and other corresponding resistance values could be
measured according to the characteristic curve in above drawing. Analog method could also be applied in measurement.
Use an electric blower to blow air into the sensor (pay attention not to keep them too near), and observe the change of
resistance, which should decrease at the moment.
Pressure sensor: Place the multimeter at DC voltage gear and connect black rod to ground, red rod to pin 3, pin 4. pin 3
should have 5V Voltage Reference In idle speed condition. Pin 4 voltage is about 1.3V(detail values are related to car type)
.Open the throttle slowly in no-load condition, the pin 4 voltage changes little. Open the throttle quickly, pin 4 voltage will
reach to about 4V(detail values are related to car type),then decrease to about 1.5V(detail values are related to car type)
VIII. Examination of Water Temperature Sensor
Resistance k
Engine ECU
Water temperature sensor
Allowable
resistance range
118
Содержание JL481Q
Страница 1: ......
Страница 9: ...5 Fig 3 Components Assembly Drawing of MR479Q MR479QA Engine ...
Страница 10: ...6 Fig 4 MR479Q MR479QA Engine and Its Power System ...
Страница 11: ...7 Fig 5 Assembly Drawing of Engine and Its Auxiliaries MR479Q MR479QA ...
Страница 12: ...8 Fig 6 Electronic Control Fuel Injection System in Engine MR479Q MR479QA ...
Страница 13: ...9 Fig 7 Front view of Engine JL481Q MR481QA ...
Страница 14: ...10 Fig 8 Sectional elevation of Engine JL481Q MR481QA ...
Страница 15: ...11 Fig 9 Electronic Control Fuel Injection System in Engine JL481Q MR481QA ...
Страница 21: ...17 Fig 13 Exterior Feature of JL481Q Engine Power Me N m Torque Pe Kw ge g kwh Fuel Consumption Ratio ...