On certain vehicles, the structure of the pressure reducing valve on the fuel filler cap is improper. If left unfixed, the air tightness of the valve may be impaired, and in the worst case, fuel leakage occurs. In addition, on some of the vehicles, the air tightness between the filler neck and the filler cap is impaired when the filler cap with the factory approved replacement valve is put in place, because the welded part for holding the fuel filler cap is wrongly positioned on the filler neck, so there is a possibility of fuel leakage. Incidentally, a recall for the latter problem was notified on 7 September 2000 and issued 16 September 2000, after it was found that the filler cap with the factory approved replacement valve (recall issued on 22 August 2000, RJ-0659-0) could not be tightened properly.