Fuel sender Citroen c2

ADU
1

Have connected Citroen c2 fuel sender to the adu

Analogue 3 one side signal ground the other side

Tried 5v pull-up to analogue 3 with various resisters

Tried all pull-up and pulldown software options

Also tried switching to analogue 1

Whatever I try the analogue just reads either 4.94v or 0v

Anyone have any ideas what I can do to make it work?

Thanks

Ben

2

How are you getting on with this?

Thought I’d chime in so you know someone is thinking about this.

Do the two wires come directly from each side of the fuel level resistor to the dash?

I ask this so I can figure out the circuit design.

Also is the car a later C2 or earlier one?

3

Thanks for the reply!

have got no where so far.

It’s 2 wires direct from The sender, it’s a later model c2

Thanks

4

Ok.

Since I don’t know what you have tried with the physical circuit.

I will assume you have continuity the full length of both wires and neither of them are shorted to ground or open.

I will assume you have access to the pump hanger and the float for testing purposes.

Since this is two wire design the computer needs to monitor the high side of the circuit to see the voltage variations caused by the variable resistor.

For this to work the computer needs an external resistor in series from the 5v supply and watches the voltage between the external resistor and the fuel tank resistor.

I would expect a Pulldown to work in this case.

Splice your analogue input between the two resistors.

With this configuration you should see 5 volts if resistance is high at the tank, and about 0.5 to 1v (or maybe 0 in your case) when resistance is low at the tank.

You can only know if it works by moving the float through its full range of motion.

Hope this makes sense.

5

Thanks for your help

found it to be a fault pin inside the sender I. The end had tested everything up till that point before but hopefully this will all help someone else with similar issues