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O2 sensor?

Discussion in 'Ford Trucks' started by WOODY367, Jan 7, 2008.

  1. WOODY367

    WOODY367 Senior Member
    from LI, NY
    Messages: 468

    My 04 F250 5.4L has a engine code. It comes up with "O2bank1 sensor signal stuck lean" I have been told to replace the sensor. Which one is it?Does this truck have 2 or 4? and should I replace just the 1 or all? The truck has 45000 miles. Thats
    P.S This code popped up a few weeks ago and the guy cleared it and said see if it comes back.
     
  2. tom_mccauley

    tom_mccauley Senior Member
    Messages: 465

    try cleaning the Mass air flow sensor, and see if the code goes away. The MAF is USUALLY what causes O2 to go lean. bank 1 will be left side of motor probably the pre converter sensor. also check for vaccum leaks. There are two sensors on a 5.4l 1 before converter 1 after
     
    Last edited: Jan 8, 2008
  3. WOODY367

    WOODY367 Senior Member
    from LI, NY
    Messages: 468

    How do you clean it? with what? Thanks
     
  4. tom_mccauley

    tom_mccauley Senior Member
    Messages: 465

    remove the cold air duct remove the MAF and use carb cleaner (no It will not hurt the plastic)
     
  5. MBB

    MBB Senior Member
    Messages: 129

    You might want to check the vacume (around an 1" in dia.) hose from the mas to the valve cover. they like to rot out at a particularly sharp bend. Causes vacume leak shows up as code you described. hose is a dealer only part Not something you can see or get a hand on as far as the area concerned I think the cost was around $50. easy fix. pain to track down sometimes you can hear it. we used a detector for leaks to find it.
     
  6. tom_mccauley

    tom_mccauley Senior Member
    Messages: 465

    The easy solution for checking this (with engine running) spray carb cleaner on elbow and listen for RMP's to increase. If they do increase, you have a leak.
     
  7. MBB

    MBB Senior Member
    Messages: 129

    I forgot about that trick
     
  8. tim096

    tim096 Senior Member
    from wny
    Messages: 100

    do you have access to a good scanner ? a scanner that can read pids? if you do the best thing to do is ck your long and short fuel trims. they should read around 0 plus or minus 5 if you have one that reads 15 or higher and stays thier you most likely have a vacuum leak the most common spot is behind the throttle plate down theon the bottom were the pcv elbow is. it is a pain to get to but very common. using carb spray is a way to find a leak if you dont have a smoke machine but not real safe {fire}. if you do use carb spray do it while watching the fuel trims with the scan tool .
     
  9. WOODY367

    WOODY367 Senior Member
    from LI, NY
    Messages: 468

    No I do not have acess to a real good scan tool. I have a basic unit. I will try the cleaning of the MAF sensor and for the vac. leaks first. I hope to get to check it tonight. Thanks
     
  10. Mudman78

    Mudman78 Senior Member
    from NJ
    Messages: 103

    There are four O2 sensors. Two before the cats (one on each side of the engine) and two after the cats (one on each side).
     
  11. tom_mccauley

    tom_mccauley Senior Member
    Messages: 465

    bank 1 pre and post converter (left side) and bank 2 pre and post converter (right side)
     
  12. WOODY367

    WOODY367 Senior Member
    from LI, NY
    Messages: 468

    Ok, I cleaned the MAF sensor and checked for vac leaks "all good'. cleared the code and will see what happens. The code did state bank1 #2 sensor which I guess would be after the CAT. If the code returns should I replace the 1 or all O2 sensors? I was told by a mechanic the you should change all O2 sensors every couple of years as the start to go bad and effect the fuel mileage. Do know if thats true but thats what I was told.
     
  13. tom_mccauley

    tom_mccauley Senior Member
    Messages: 465

    Bank 1 #2 would be after converter, and yes I would just change both o2 sensors in bank. Usually when one fails the other will fail with in a short amount of time.
     
  14. Mudman78

    Mudman78 Senior Member
    from NJ
    Messages: 103

    If it's the after cat sensor then it's only one of two things. Either the sensor is bad or the cat is starting to plug up. If it goes off again, change both sensors on that side. If it happens again after that, get it to the dealer before your 5yr./50,000 mile Federal Emission Standards Warranty expires and they'll replace the cat for free.

    .....come to think of it, the O2 sensors should be covered under that warranty as well. Check the warranty manual that came with the truck.
     
  15. WOODY367

    WOODY367 Senior Member
    from LI, NY
    Messages: 468

    Thanks for the warrenty info. I forgot about that and will keep it in mind if it keeps happening.