wire colors Rear Oxygen Sensor C5 EW10 2009

[PelleT]

Hi everyone,
I'm about to replace the rear O2 sensor (after the cat) in a 2009 C5 gasoline (Flexfuel). Bought a generic with following wires: 2 x White, Black and Gray. Wires comming from the car are: White, Purple, Black and Gray. The new sensor came without a connector (beside the fact that the cable is too short) so I'll solder it to the old sensor cable. My simple question is: How to connect? (I have seached this forum but cannot find this info)

Connections for the new senor are: the two White wires are for the internal heater, Black is signal and Gray signal ground.

Also... Can I detect/measure the cable that comes out from the car to find the configuration? The obvious one will be heater+ (12V -ish) but how to find the other three?
Greetings from Sweden

[mickthemaverick]

In general Citroen wiring is identified by numbers printed along the wires as colours may vary. The wiring diagram for the old sensor will give the numbers of each wire for you to identify them on the car and then you can connect them accordingly.

[PelleT]

Thanks mickthemaverick, Interesting way of identifying wires, might be more flexible that colors.

Next question, Where can I find a good e-diagram, Have no problem to pay for it if necessary?

[mickthemaverick]

For the information I can access, I need to know the following details about your vehicle:

Make/Model
Year
Engine type
Gearbox type
Body style
LHD or RHD
RPO number which can be found on the tyre pressure sticker on the door pillar, post a picture of the sticker if you are not sure.
Whether the vehicle has Electronic Stability Control or not

Given that information I can access the Citroen Servicebox and Sedre backup systems for vehicles up to 2012 and copy from there.

[mickthemaverick]

By guessing some of the info I need I have found this diagram which shows both Oxygen sensors at the bottom numbered 1350 (front) and 1351 (rear). My guesses were C5 X7 Saloon EW10 with AL4 gearbox, LHD and RPO 11890. If your details are radically different let me know and I'll look again.

C5 X7 Ignition.pdf

Copied from backup

(669.92 KiB) Downloaded 21 times

You will find this guide helpful in decyphering the diagram:

viewtopic.php?p=782862#p782862

[PaulC5]

Why are you having to replace the sensor ? Sometimes copy ones do not work as well as ones from a dealer so something to be aware of if it does not work too well once installed. If you are cutting out the complete connector, do not throw it away in case you have to buy a sensor from a dealer and then need to connect it.