The Wipeout has no Actice Radar. It has only Vis or IR Sensors.
You have to see your target either through the target pod or the front sensors. Remeber both have a limited angle.

Thanks but how do I lock on then?
I tried with T or from the pod and it just makes a square around the target but no diamond lock or sound

What weapon?

AG

Right here's the update of my situation
When I'm in the wipeout and I see an enemy I lock with T, a box apears around the target but there is no lock on to the target so all the weapons are just dumbfire

Using the AG asure that the plane is in the firing angle that is in a 60° Cone in Front of the plane. The Target Pod is for aquiring and locking targets. the "real" lock is done by the Weapon and that is looking in the front

https://youtu.be/GmrinHR6YE8

Wipeout does not have active radar anymore, only "passive" radar, i.e. can detect other radars active in the area. It has a visual and IR sensor, and its weapons use IR lock. The target object must be hot (i.e. have its engines on) for successful lock. they've improved locking behaviour in 1.72, btw.