Heated Exhaust Gas Oxygen (HEGO) sensor - removal and refitting

Note: A new sealing ring will be required on refitting.

Removal
1 Apply the handbrake, then jack up the front of the vehicle and support it on axle stands (see “Jacking and Vehicle Support”).

2 Disconnect the battery negative lead.

3 Unclip the wiring and disconnect the sensor wiring plug (see illustration).

17.3 Heated exhaust gas oxygen (HEGO) sensor - 1.4 CFI engine
17.3 Heated exhaust gas oxygen (HEGO) sensor - 1.4 CFI engine

A Sealing ring
B HEGO sensor
C Sensor shield

4 Remove the sensor heat shield, then unscrew the sensor from the exhaust downpipe, and carefully remove it complete with sealing ring.

Warning: Do not touch the tip of the HEGO sensor.

Refitting
5 Refitting is a reversal of removal, bearing in mind the following points.

6 Clean the sensor threads, and take care not to touch the tip of the sensor during the refitting procedure.

7 Use a new sensor sealing ring.

8 Tighten the sensor to the specified torque.

9 On completion, start the engine and check for leaks between the sensor and the exhaust downpipe.

    See also:

    Engine compartment overview - 1.25L Duratec-16V (Sigma)/1.4L Duratec-16V (Sigma)
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    Switching off the engine
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