I am facing a problem in fuel mileage my avalon showing is less..I filled the fuel tank full but it reads maximum 360kms & than start going down while running .I feel with full tank capacity it must read more than 450kms..which sensor in car responsible for measuring mileage showing in screen. |Do i need to change all brakes together i mean both front/back side.How to know whether my brakes are in good shape. i have avalon 2004 XLS.I am using remote to lock unlock & truck.But like other cars when u press lock/unlock a horn sound also comes with that.But its not happening in my avalon.How to do it.

As for your gas two possible things, the actual float inside the tank could be sticking, or the actual gauge behind the dash is bad. as for your brakes, if you here alot of grinding when your trying to stop, or constant squealing or you feel like your breaks are catching and then releasing and catching again (kind of jerky stops when u hit the breaks) this can be some more signs.. (do it when its dry, water can cause the breaks to squeak sometimes.)

as for the horn, not all cars/trucks have that feature. IF it does it just be a wiring issue. Something a mechanic could easily check and fix at the same time your getting your breaks or the gas gauge fixed.

If the fuel gauge is lowering as you drive,and the fuel is still in the tank,then I would gather that,the fuel gauge sending unit in the fuel tank is not working correctly,and needs to be replaced.Brake repair comes in replacing ,both front,and then both rear.The brake pads are purchased in sets,front set,and rear set.These sets service one axle.To inspect the brake pads,the brake pads will have a sensor,made of steel,that will move closer to the brake rotor as the brake pad has worn down.If the sensor(made of steel)touches the rotor,it will squeal.If it does this,it is time to change the brake pads.The sensor does not always work correctly,and will not squeal,or can not be heard.To look at the brake pads,to see if they are ready to be changed,there will be about a 1/8 inch of pad left,and it is time to do a brake job on that axle.Check both sides,left,and right wheels,if one side is worn more than the other,do the brake job.Removal of the brake pads is a good idea.This way,you can see if there is any cracking in the brake pad itself.This is to be done for the front,and the rear.The front brake pads will where out two,to three times compared to the rear.This would be normal.As respect to the horn sounding upon remote unlock,well,it should be operational,make sure the horn works,I hardly ever use mine,so I would think you would not either,but depending on where you live,right? So if it is not sounding upon key less remote,then The control box may have a bad circuit for that out put.Replacement of the control box might be the thing to do.To install the hardware to do this,would only take wire.Come off the actuator controlling the door lock on the drivers door,and go directly to the horn,you will get a short burst from the horn.The actuator in the door only requires one wire to unlock,and lock the door,this is all you need to sound the horn one time.The short beep beep,would require a delay relay to be installed. I hope this is what you needed as far as information,and if it was at all helpful,please let us know,thank you.