Crazy Question On P0174 Code

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.

DTC P0174: Front Bank (Bank 2) Fuel System Too Lean
P0171-1470
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
OBD Status PASSED/FAILED/NOT COMPLETED (STILL TESTING)
Advanced Diagnostics
+
-
Short Term Fuel Trim
Long Term Fuel Trim
+
-
Normal Operation System Failure (Too Lean)
0% 0%
Threshold
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.
P0174TTP6DAA010AN
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!