Nissan Repair: 2000 Nissan Altima, fuel tank level, nissan altima

Question
Recently purchased this car with 95k miles. The SES light came after driving about one tank of fuel. the light came on then back off several times. I caught it on and had it checked. I had knock senser code and a catilic converter code. I replaced the converter. Nissan said it would take care of problem. Nissan reset the SES alarm . 300 miles later the SES light is back on. Codes now are P0325 and P1126. I know the PO325 is knock sensor. I get conflicting information on the P1126 code. Please advise me on what to do. I plan to change the faulty part or parts myself. I can not afford otherwise now after the converter replacement.Car runs great. I did notice ech time the SES light comes on the fuel tank level was aroung 1/4 tank or less. I replaced the fuel filter. Thanks, Tim

Answer
Tim,

I would check the P1126 again as it is for a throttle control motor relay.  I suppose this could be a possibility but I would think the repair on the converter would not have caused this.  Now, after 300 miles I would be going back to the dealer and get this problem addressed since they should warranty their work.  They have the Consult II scantool and that should be able to pinpoint the problem.  If they changed the converter and not the knock sensor they should change the knock sensor.  The fuel should not be a cause.  You could disconnect the battery for a five minutes and reconnect to clear the codes and see if they will stay gone.  But, I have seen too many knock sensors on Altimas...