@how much air pressure requir in front / rear tyre of hundai accent CRDI 2006

you should be running 8 ply tyres on the vehicle to carry the maximum load as required by the regulator
The recommended tyre pressure will be on a decal attached to the drivers door ( probably on the door frame under the latch)
Having said all that I recommend 45 psi for the rear and 40 for the front
If you run any less ,the ride will be smoother but if you load the vehicle, the rear tyres are under inflated and prone to failure from overheating
tyres are manufactured to run at a certain pressure due to the construction of the case. Talk to a tyre shop as to the pressure you should be using for the tyres.

32psi front and 29psi rear

location of oil pressure sensor on 02 hyundai accent gl with a 1.6 liter engine is driver side front of engine. lower near the bottom of the radiator.mind you that is for a 1.6 l

if you have tires with size :235/40ZR18 unloaded & loaded 40psi
if you have tires with size 235/55x17 45psi

are you sure they didnt change fronts to rear so that you would have the safest tyres on the front???
From my experience,working for hyundai, you would be lucky to get 25/30k from a pair of fronts and about 50 from the rears......
also, as tyres are relatively cheap, why would they swap for a pair of old,worn tyres,dont make sense...... (its easier to go to a parking lot at night and steal all four from a new car........)

30psi front 30psi rear

DEPENDING ON TYPE OF TYRES IT SHOULD BE 2.2BAR LOOK ON THE TYRE PRESSURE IS PRINTED ON THE TYRE

Read the Owner's Manual

Brake booster specs ("Save picture as" to another location and use ZOOM IN utility to have a better view.

ok have you checked that the tyre pressure is the same on all four wheels or it could be that the rear axel is not being lubricated properly check the bushing.