Late intimation u/s 143(1)

As per sec 143(1) if there is any arithematical mistake in your return then you will be served a noitce u/s 143(1) for the payment of difference amount of tax.
As you told u received that intimation after 1 year, its poor in serving of intimation but it doesnt mean that u will b escaped from tax liability.
if you do not deposit difference amount of tax AO will take your case in scrutiny u/s 143(3).
so you should deposit difference of tax,if any, in excess of tax claimed in return.
if AO levi any penalty or interest on non compliance of intimation then u can take the stand against interest or penalty on the basis of delayed intimation.