Oxygen sensor wiring diagram (3S-FE, 4A-FE, 4S-FE, 7A-FE): 1 - oxygen sensor, 2 - to the main relay of the fuel injection system, 3 - diagnostic connector, 4 - electronic control unit
1. Warm up the engine to normal operating temperature.
2. Measure the oxygen sensor feedback voltage.
3S-FE, 3S-GE. 4A-FE, 4S-FE, 5E-FE
- a) Connect the positive terminal of the voltmeter to the "VF1" terminal of the diagnostic connector, and the negative terminal to the "E1" terminal and perform the test according to the given algorithm.
7A-FE
- a) Start the engine.
- b) Warm up the engine to normal operating temperature.
- c) Connect the positive lead of the voltmeter to the "VF1" terminal of the diagnostic connector, and the negative lead to the "E1" terminal.
- d) Run the engine at 2500 rpm for 2 minutes.
- d) Let the engine idle for 10 minutes.
- e) Increase engine speed sharply (2-3 times).
- g) Set the rotation speed to 1500 rpm.
- c) Measure the voltage between terminals "VF1" and "E1".
Nominal value: no more than 1 V.
- i) Set the idle mode.
- k) Measure the voltage between terminals "VF1" and "E1".
Nominal value: (at 700±50 rpm) not less than 4.3 V.
3. (3S-FE, 3S-GE, 4A-FE, 4S-FE. 7A-FE) Measure the resistance of the oxygen sensor heater by connecting an ohmmeter to the "+B" and "HT" terminals.
Nominal resistance (at t = 20°C):
- 3S-FE, 3S-GE, 4A-FE and 4S-FE: 5.1-6.3 Ohm
- 7A-FE: 1.5-2.10 Ohm
If the resistance value is outside the specified range, replace the oxygen sensor.
Oxygen Sensor Fault Finding Algorithm
