Honda Accord Check Engine Light Codes: 1456 & 0171

Discussion in 'Accord' started by techjohnny, May 6, 2008.

  1. techjohnny

    techjohnny Guest

    I spent several hundreds dollars to pass emissions last month. I was
    receiving eCU codes P0401 and P0420, which were both resolved after
    the shop replaced my Catalyst Converter and O2 sensor, but now the
    "Check Engine" light is back with the following codes:

    0171 and 1456

    I knew something was wrong since the car had troubles accelerating
    after being at a complete stop. It will jerk and sometimes jump.
    I've never seen these two codes before having the shop work on my
    car. Could this be just a mere coincidence or should the shop help
    fix the problem?

    The Catalyst converter was after market.

    techjohnny, May 6, 2008
  2. 5/6/08
    Would have been nice to have the year of the vehicle.

    0401 code-Sound like the EGR system was acting up before. I assume you have
    an EGR system or you wouldn't have gotten the 0401 code. Ask the mechanic
    that worked on it if he addressed that issue. Some on this newsgroup think
    that a faulty EGR system will cause problems with the cat conv but I can't
    confirm or deny that. 0420 is catalytic conv efficiency is low. That should
    have been corrected with the new cat.

    0171 is fuel system too lean. Could be a LOT of different problems. Plugged
    fuel filter. MAP sensor. Primary O2 sensor. Bad fuel-drain tank and refill.
    Valve clearance incorrect. Exhaust leakage. Check for air leaks into the
    intake manifold. Could be an oxygen sensor problem. A garage with good
    diagnostic skills should be able to tell you. Perhaps the group will chime
    in on this code with some more ideas.

    1456 is a problem with the evap emissions control system. Start by making
    sure the gas cap is on tight. Try a known good gas cap on it. After that you
    need some trouble shooting skills. There is a solenoid that controls vacuum
    to the purge canister to clean out the fuel fumes. Perhaps there is a leak
    in that hose and when the solenoid opens it lets in raw air (thus the lean
    mix) instead of the expected gas fumes (richer mix). Not much but a place to

    Please remove "yourpants" to reply
    1998 Civic HX MT with 142K
    2000 CRV EX MT with 98K
    delbert brecht, May 7, 2008
  3. techjohnny

    techjohnny Guest

    Thanks for the feedback. It's a 1998 Honda Accord 4cyl EX with 212K
    miles with a recently replace transmission (50K miles ago).
    techjohnny, May 7, 2008
  4. techjohnny

    techjohnny Guest

    Thanks for the feedback. It's a 1998 Honda Accord 4cyl EX with 212K
    miles with a recently replace transmission (50K miles ago).
    techjohnny, May 8, 2008
  5. techjohnny

    Tegger Guest


    The OP has not said the year of his Accord, as you point out.

    There are numerous TSBs involving P0171 and P1456. These are year (and
    sometimes engine) specific.

    Honda's EVAP systems are notoriously trouble-prone with several known
    issues that set a P1456. It turns out that underneath the back of the car
    is not the best place to install something as sensitive and finicky as the
    currently mandated EVAP system.

    To the OP: Please provide year and engine of your Accord. Also state trim
    level (EX, LX, Hybrid, etc.)
    Tegger, May 8, 2008
  6. techjohnny

    bi241 Guest

    i suspect that your Accord has on-going leaking injectors problem
    leaking injectors will cause the EGR valve, catalytic converter and
    EVAP system to fail, and result in poor drivability and bad fuel

    inspect and fix the injectors first, a bottle of fuel system cleaner
    may do it.

    you dont want to buy another cat for the next emission check, yes?
    bi241, May 8, 2008
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