Crazy Question On P0174 Code

Discussion in '1996 - 2004 SN95 Mustang -General/Talk-' started by justadodgeman, Jun 16, 2014.

  1. so as most of yall know me and my dad have been battling this code for a while and we finally thought we got it after cleaning the terminals(yeah I know not likely but weve both seen crazier. well it stayed off for like 3 weeks and today we recharged the ac(hasn't been working since we got it running and as of recently when we cleaned the terminals and replaced a leaky radiator it stopped clicking on or anything) well as soon as we started recharging it and it started clicking off an on the code came back on. so I know its a crazy question but could the ac system have anything to do with this code(lean bank 2)? I have done everything yall have suggested and even some extra stuff and it hasn't fixed it.
  2. oh and I think there is a leak to cause the ac started blowing hot air again shortly after
  3. Lean on bank 2 is a possible exhaust leak. Maybe the refrigerant is leaking in the area of an exhaust leak?

    If the code came on during the recharge it is likely just a coincidence. It could take up to a day for the code to set once an issue is detected.
  4. the code had been off for almost a week of driving(probably around 150 miles
  5. Yes...sometimes a week. It's not an exact science. I have a lean condition in my car as well but it doesn't come on until it idles for a long time. That is why I think you may have an exhaust leak.
  6. alright so you have an exhaust leak which causes a lean code when you idle for a long time well I was idling for a while to recharge the ac but I have checked up and down for any exhaust leaks before the front o2s and the only leak I found was in the cat and in the muffler from where it had bottomed out somewhere and I welded those places
  7. Here is my internet diagnosis. You have a leaky gasket on bank 2, drives side. When the A/C compressor pulls a load on the engine the leak gets worse. First thing I would do is a smoke test to rule this out, or take a chance on changing the intake gaskets. Seems like if there was a vac leak in a vac hose the whole engine would run lean, but not totally out of the question. Changing those gaskets is cheap and quick.

    I would also say that a failing injector could be a possibility, but a smoke test provided you have the tools and resources would rule out any type of vacuum leak.
  8. DTC P0174: Front Bank (Bank 2) Fuel System Too Lean
    General Description
    The powertrain control module (PCM) detects the oxygen content in the exhaust gas from the front air/fuel ratio (A/F) sensor
    (bank 2, sensor 1) signal voltage, and it uses fuel feedback control to maintain the optimal air/fuel ratio. The air/fuel ratio
    coefficient for correcting the amount of injected fuel is the short term fuel trim. The PCM varies short term fuel trim
    continuously to keep the air/fuel ratio close to the stoichiometric ratio for all driving conditions. Long term fuel trim is
    computed from short term fuel trim and is used to regulate long term deviation from the stoichiometric air/fuel ratio, which
    occurs when fuel metering components deteriorate with age or system failures occur. In addition, long term fuel trim is stored
    in the PCM memory and is used to determine when fuel metering components malfunction. When long term fuel trim is
    higher than normal, which is about 1.0 (0 %), the amount of injected fuel must be increased, and when lower than normal, it
    must be decreased. If long term fuel trim is higher than normal (too lean), the PCM detects a malfunction in the fuel metering
    components and stores a DTC.
    Monitor Execution, Sequence, Duration, DTC Type, OBD Status
    * : The malfunction parameters are cleared when it is judged as normal under the same driving conditions in which the
    malfunction was detected.
    Execution Once per driving cycle*
    Sequence None
    Duration Every 7.0 seconds
    DTC Type Two drive cycles, MIL on
    Advanced Diagnostics
    Short Term Fuel Trim
    Long Term Fuel Trim
    Normal Operation System Failure (Too Lean)
    0% 0%
    Enable Conditions
    Malfunction Threshold

    Long term fuel trim is higher than 1.33 (+33 %).
    Driving Pattern
    1. Start the engine. Hold the engine speed at 3,000 rpm without load (in P or N) until the radiator fan comes on.
    2. Drive at a steady speed between 15 - 75 mph (24 - 120 km/h) for at least 15 minutes, and watch the long term fuel trim. If
    the long term fuel trim stays at about 1.0, the vehicle is OK or it is a very minor problem. If a significant fault is still present,
    the long term fuel trim will move up or down while driving.
    • When freeze data is stored, drive the vehicle under those conditions instead of Driving Pattern step 2.
    • After clearing the DTC by disconnecting the battery or using the scan tool, extend Driving Pattern step 2 to 40 minutes or
    longer to allow time for long term fuel trim to recover.
    • Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.
    Diagnosis Details
    Conditions for setting the DTC

    When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction
    returns in the next (second) drive cycle, the MIL comes on and a Confirmed DTC and the freeze data are stored.
    Conditions for clearing the DTC
    The MIL is cleared if the malfunction does not return in three consecutive drive cycles in which the engine conditions are
    similar to the first time the malfunction was detected. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data
    can be cleared with the scan tool Clear command or by disconnecting the battery.
    Condition Minimum Maximum
    Engine coolant temperature 156 ºF (69 ºC) —
    Intake air temperature 19 ºF (-7 ºC) —
    Engine speed 500 rpm 4,000 rpm
    MAP value 22 kPa (6.3 inHg, 160 mmHg) —
    Fuel feedback Closed loop
    Monitoring priority P0420, P0430
    No active DTCs set (prevents
    monitor from running)
    P0107, P0108, P0112, P0113, P0117, P0118, P0154, P0155, P0157, P0158, P0159,
    P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0335, P0339, P0351, P0352,
    P0353, P0354, P0355, P0356, P0443, P0496, P0497, P0627, P1128, P1129, P1174,
    P145C, P2197, P2227, P2228, P2229, P2240, P2241, P2247, P2249, P2254, P2255,
    P2272, P2652

    Hope this helps!