Download For 2003 and 2004 Applied Vehicles: When you perform Procedure C (ECM Reprogramming), go to NTB06-051a for reprogramming information. You will still need to perform all other parts of this bulletin on 2003 and 2004 Applied Vehicles. INTRODUCTION Nissan has determined that some 2002-2003 model year Altima and 2002-2004 model year Sentra vehicles equipped with the 2.5 liter engine have defects that relate to motor vehicle safety. For 2002-2003 model year Altimas, there is a possibility that the exhaust pipe hanger pin may catch debris from the road that could be ignited by contact with the catalytic converter and cause a fire. In addition, for 2002-2003 model year Altimas and 2002-2004 model year Sentras, there is a possibility that certain engine operating conditions may cause damage to the pre-catalyst. Material from inside a damaged pre-catalyst could enter the engine and result in increased oil consumption. If the engine oil level is not checked on a periodic basis and drops below the low level, and the driver continues to operate the vehicle ignoring noticeable engine noise, engine damage may occur which could result in a fire.