Technical ECU ground cable

[dddsiv]

Hi, I found this grounding cable for ECU, that is connected to the body of the car, but is not connected to ECU. I don't see any logical place to connect it to ECU. I don't have any electrical problems, only error code for bad catalytic converter. Does anyone know where to connect it?

 

[GrandePunto PL]

Upside down thinking.
It is connected to the ECU.
It is not grounded to the chassis/body (that's the purpose of the loop/ring/lug O-type terminal). Or the ECU mount/bracket(?).
Find the nearest place to bolt it down, must be somewhere (leave some free length to accommodate for the engine movement, don't stretch the wire).

PS
Year 2014 and you've managed to kill the cat. converter? What happened (total neglect, lack of maintenance)?

 

[dddsiv]

But cable is clearly connected to body, and the part that is oriented to the ECU is not connected (cable has O type connector on the both sides). I don't know about the cat, I bought it that way

 

[dddsiv]

It Is this cable

 

[GrandePunto PL]

So it's an ECU ground BYPASS then (probably - wait till someone confirms, "2012" owners).
To protect the ECU in case of main ground failure. It probably goes to the ECU bracket/mount - car body.
You don't want to power starter motor for example, partially via ECU PCB traces.
Some ECUs should NOT have GND on the casing anyways, I mean, it's not connected internally (older versions like Grande/EVO are not grounded, there is like 100kΩ resistance from the aluminium ECU case to the GND wires in the plugs/connectors).

Wire like that can also protect the ECU from the ignition system faults (or owner/mechanic mistakes), high voltage spikes etc.

Try Google Images (even reverse search your own car). Engine bay, Punto 2012 (1,2 8V).
Example. Wire goes somewhere behind the ECU and a bit down.

 

[dddsiv]

I saw this in one video

so I connected it to the ECU housing like this