Structure and circuit of throttle position sensor

Linear output throttle position sensor

The structure and voltage output characteristics of the linear output throttle position sensor are shown in figure 1. Its two contacts (or contacts) are connected with the throttle shaft, and one contact can slide on the resistor, and the throttle position signal is converted into voltage value VTA through the change of the resistor. This voltage varies linearly, so this sensor is called linear output throttle position sensor. According to this linear voltage value, the ECU can sense the opening of the throttle valve, so that the ECU can correct the fuel injection quantity, while the other contact is in contact with the idle contact IDL when the throttle valve is fully closed, and the IDL signal is used to control the fuel cut and the ignition advance angle. The linear output throttle position sensor is also called variable resistance sensor or sliding resistance sensor, and its connection circuit with ECU is shown in Figure 2.

Figure 1 Structure and characteristics of linear output throttle position sensor

Vc- power supply; VTA- identifies the output signal of the throttle position sensor; IDL- idle contact, E2- ground

(2) Detecting the Toyota linear output throttle position sensor.

The engine of Toyota Crown 3.0 adopts linear output throttle position sensor, and its overhaul contents mainly include idle contact conduction, sensor resistance and sensor voltage.

① Check the conduction of the empty contact. Turn off the ignition switch, unplug the wire connector of the throttle position sensor, and check the continuity of the IDL contact on the wire connector with a multimeter, as shown in Figure 3. When the throttle valve is completely closed, the IDL-E2 terminal should be connected with zero resistance; When the throttle valve is opened, there is no conduction between IDl-E2 terminals, and the resistance is infinite. Otherwise, replace the throttle position sensor.

Fig. 2 Connection circuit diagram of linear output TPS and ECU

3 Check the conduction of the empty contact.

② Sensor resistance check. Turn off the ignition switch and pull off the part.

Valve position sensor connector, measure VT with multimeter resistance.

The resistance between E2 should increase linearly with the increase of throttle opening. Sensor resistance check is shown in Figure 4. A sum

Insert gauges with different thicknesses between the throttle limit screw and the limit rod, and measure the resistance between the terminals on the sensor wire connector with a multimeter resistance file. The resistance value shall conform to the specified value in table 1.

③ Sensor voltage check. Plug back the wire connector, turn on the ignition switch and connect IDL and Vc.

The voltage value between —E2 shall comply with the provisions in Table 2. There should be voltage on the three terminals of VTA. Use multimeter to measure IDL-E2, VC-E2 and VTA.

Figure 4 Sensor Resistance List 1 Resistance between terminals of linear output throttle position sensor

Table 2 Voltage between Throttle Position Sensor Terminals

④ Adjustment of throttle position sensor. Loosen the two fixing screws of the throttle position sensor, as shown in Figure 5(a), insert a gauge with a thickness of 0.50mm between the limit screw and the limit lever, and check the continuity between IDL and F with a multimeter, as shown in Figure 5(b). Turn the throttle position sensor counterclockwise to disconnect the idle contact, and then slowly turn the throttle position sensor clockwise until the idle contact is closed. At this time, the electric gear of the multimeter shows a reading, and then tighten the two fixing screws. Secondly, the gauges with the thickness of 0.45mm and 0.55mm were inserted between the limit screw and the limit rod, and the continuity between the IDL and the frame was measured. When using 0.45mm thickness gauge, IDL and E2 terminals should be connected; When using 0.55 mm thickness gauge, there should be no conduction between IDL and island terminal. Otherwise, the throttle position sensor should be adjusted again.

(3) Detection of linear output throttle position sensor of Santana 2000GSi car.

Jetta GT, GTX and Santana 2000GSi car engines all use linear output throttle position sensors, and their structural shapes and connection circuits are shown in Figure 6.

Fig. 5 Adjustment of throttle position sensor

When the throttle position sensor fails, the engine ECU can diagnose it and make the engine run in an emergency. With the V.A.G.1551or V.A.G.1552 scan tool, the fault information can be read through the fault diagnosis socket.

When repairing the linear output throttle position sensor, the power supply voltage and signal voltage can be measured by multimeter. The standard data of TPS for Santana 2000GSi car is shown in Table 3, and it should be overhauled. If the voltage value is greater than the value specified in the table, the sensor is damaged and should be replaced.

When checking the resistance, please turn off the ignition switch and unplug the wire connector. The resistance between terminals on two plugs of ECU and sensor shall meet the requirements in Table 3. If the resistance is too large or too small, it means that the harness terminal is in poor contact and should be repaired.

Fig. 6 Santana 200065 1 linear output throttle position sensor.

1 power supply voltage (5v); 2. Signal output terminal; 3 grounding terminal

Table 3 Maintenance Standard for Throttle Position Sensor of Santana 2000GSi Car