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• OVERALL DIFFICULTY INDEX: 3/10
• IF YOU HAVE NO TOOLS, YOU PAY $45 TO GET THEM FOR THIS JOB
• IF YOU HAVE NO EXPERIENCE YOU SPEND 1.5 HOURS TO CARRY OUT THIS JOB
• RISK OF BURNS, SEE BELOW​​

BEFORE YOU START

• Work only on a cold engine for this intervention. Do not attempt to work on a hot engine as this concerns the exhaust system with temperatures reaching hundreds of degrees.
• Replacing the O2 sensor on other engines is identical
• This pictorial applies to the upstream sensor (sensor 1 bank 1) but the same is valid for the downstream sensor.

​DISCLAIMER:
Our pictorials are of informative nature and do illustrate works carried out by ourselves at our own premises for our own use and satisfaction.
Readers who envisage to carry out similar works inspired by the below method shall do this at their own risks and liability.

The below works concerned a Peugeot 5008 equipped with a turbo-charged PSA BMW EP6 engine.
Same or similar 1.6 VTi and 1.6 THP EP6 engines can be found on Peugeot 207, 208, 308, 508, 3008, 5008 and Citroen C4, C4 Sedan, DS3, DS4, DS5 also the Mini Cooper S. The works remain similar or identical on any oxygen sensor of any car.

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Symptoms of an ageing oxygen sensor

Typical average lifetime of an O2 sensor is 80,000-120,000 Km
This is an average, below symptoms can happen earlier:

• Difficult engine start when cold
• Long cranking time
• Rough idle at all times
• Hesitation when accelerating from idle
• Slight loss of power
• Increase in fuel consumption
• Check engine light goes on
  
• OBDII fault code generation
  

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Air fuel (A/F) or oxygen (O2) sensor removal 

1- Disconnect the battery.

2- Locate the O2 sensor connector by following its wires. Disconnect it.​

3- Remove the sensor cable from its clips all along its way to the oxygen sensor.

4- A specific 22mm socket with side cut out exists (see further below) but you can also use a spanner whenever enough space is there to hold the spanner properly. Hold the spanner firmly with one hand and give it a firm hit with the other hand to loosen the sensor, it will then unscrew very easily. ​Take off the sensor.

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Air fuel (A/F) or oxygen (O2) sensor refitting

The problem with the spanner is that you don't know to which torque your are tightening.
If the spanner is not longer than usual, then go ahead and tighten the O2 sensor to the max of your force.
​Re-route the cable carefully and meticulously and fix it at every clip. Reconnect the O2 sensor connector.
​Reconnect the battery and wait 5 minutes before starting the engine. 
Plug your scanner and erase the OBDII code that the O2 sensor had generated.

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Buy your upstream lambda sensor from our partners' stores, universal fitment models shown, vehicle compatibility to be further checked:

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Tool for air fuel (A/F) and oxygen (O2) sensor removal and refitting:

The below images do show how to use the specific O2 sensor, which is a 22mm socket:

• The side cut is for the sensor's cable. 
• The O2 sensor socket can be used like for any bolt.
• O2 sensors are tightened to 5 mKg
• This tool is universal i.e. it is not specific and fits on all O2 sensors

See also our other tutorials in relation with the EP6 Engine

EP6 Engine Repair Manual

...and buy your universal or Peugeot / Mini specific O2 sensor and tool here:

all our car repair tips