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Generally when these codes appear it is due to insufficient fuel pressure. Test your fuel pump to ensure it is within specs. Have you changed your fuel filter?
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Question edited for clarity. It is P-Zero 0, not P-oh O.
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• DTC P0171 Fuel Trim System Lean Bank 1
• DTC P0174 Fuel Trim System Lean Bank 2
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The engine control module (ECM) controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. Fuel delivery is controlled differently during Open and Closed Loop. During Open Loop, the ECM determines fuel delivery based on sensor signals without oxygen sensor (O2S) input. During Closed Loop, the O2S inputs are added and used by the ECM to calculate short and long term fuel trim (FT) fuel delivery adjustments. If the O2S indicates a lean condition, FT values will be above 0 percent. If the O2S indicate a rich condition, FT values will be below 0 percent. Short term FT values change rapidly in response to the heated oxygen sensor (HO2S) voltage signals. Long term FT makes coarse adjustments in order to maintain an air/fuel ratio of 14.7:1. If the ECM detects an excessively lean condition, DTC P0171 or P0174 sets.
Diagnostic Aids
• Excessive resistance in the fuel injector ignition 1 voltage circuit or the fuel injector control circuit may cause the following symptoms:
- Lean condition
- Misfire
- Rough idle
• The system will go lean if an injector is not suppling enough fuel.
• A lean condition could be present during high fuel demand.
• A malfunctioning MAF sensor can cause this DTC to set. Refer to DTC P0101 .
• Review the Failure Records with a scan. If an intermittent condition is suspected, refer to Intermittent Conditions .
DTC Descriptors
This diagnostic procedure supports the following DTCs:
• DTC P0420 Catalyst System Low Efficiency Bank 1
• DTC P0430 Catalyst System Low Efficiency Bank 2
This code could mean the catalytic converter on that bank has failed .
Feb 11, 2014 - 'Check Engine' code P0171 System Too Lean - Is it safe to drive? ... My question is: is it okay to drive my car while it shows these codes? ... This will cause you to get increasingly worse fuel mileage. ... I am going to defer to your expertise, but I just want to ask if you've considered that lean-running engines ...
Definition of error code P0171 and P0174 - System too Lean (Bank 1 and Bank 2). ...Before we get into the main causes of P0171, let's explore why this code matters. ..."Lean" running cars and light trucks are highly polluting vehicles. Most of ...
Question Product: Cars & Trucks Question Details: Mazda tribute codes p0171 ... I am getting the following (4) codes in a 2003 Mazda Protege5 engine: P0090 ...
code p0171 refers to system too lean bank 1===causes ---intake /exhaust leak---AIR system--MAF/VAF sensor---fuel pressure /pump---injector/s ---HO2S sensor
if it runs ok then replace the HO2S sensor in bank 1 (exhaust before the cat converter at the firewall side of the engine)
Hi there: DTC P0171 - System Too Lean (Bank 1) Basically this means that an oxygen sensor in bank 1 detected a lean condition (too much oxygen in the exhaust). On V6/V8/V10 engines, Bank 1 is the side of the engine that has cylinder #1.
Note: This DTC is very similar to P0174, and in fact your vehicle may show both codes at the same time.
You will more than likely not notice any drivability problems, although there may be symptoms such as a lack of power, detonation (spark knock), and/or a hesitation/surge on acceleration.
A code P0171 may mean that one or more of the following has happened: The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters may cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry. There could be a vacuum leak downstream of the MAF sensor.
Possible solutions include: In the vast majority of cases, simply cleaning the MAF sensor does the trick. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling Inspect all vacuum and PCV hoses, replace if necessary Check for a dirty fuel filter and proper fuel pressure
On rare occasions, a check engine light may be experienced with DTC P0171, P0441, P0455, and/or P2420. These DTCs may be a result of an internal PCM driver issue that may keep the EVAP purge solenoid control circuit grounded at times instead of supplying a pulse width signal on the circuit. ask your dealer and check this TSB: #PIP3621: DTCs P0171, P0441, and/or P2420 - Inspect Production Part Number on PCM - keywords CEL check ECM EVAP lamp lean light repeat trim updated - (Nov 9, 2005) Subject: DTCs P0171, P0441, P0455 and/or P2420 - Inspect Production Part Number on PCM
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DTC P0171 - System Too Lean (Bank 1) Basically
this means that an oxygen sensor in bank 1 detected a lean condition
(too much oxygen in the exhaust). On V6/V8/V10 engines, Bank 1 is the
side of the engine that has cylinder #1.
Note: This DTC (Diagnostic Trouble Code) is very similar to P0174, and in fact your vehicle may show both codes at the same time.
I
would suggest that you take a look at the front oxygen sensor.
Typically speaking the oxygen sensor causes this code to appear. Here is
the possible cause list from the manual for your car.
Trouble Code: P0171 - Fuel System Lean (Bank 1)
Possible Causes: Air leaks in intake manifold, exhaust pipes or exhaust manifold Base engine mechanical problem causing a lean A/F condition Fuel control Sensor is out of calibration (e.g., ECT, IAT or MAP) Fuel delivery component fault (clogged filter, low fuel pressure) O2 element is contaminated, deteriorated or it has failed Vacuum hose is disconnected, broken, leaking or loose
Hope this helps (remember to rating this answer ans leave us a testimonial comment). Thank you for using FixYa.
DTC P0171 - System Too Lean (Bank 1) Basically this means that an oxygen sensor in bank 1 detected a lean condition (too much oxygen in the exhaust). On V6/V8/V10 engines, Bank 1 is the side of the engine that has cylinder #1.
Note: This DTC (Diagnostic Trouble Code) is very similar to P0174, and in fact your vehicle may show both codes at the same time.
I would suggest that you take a look at the front oxygen sensor. Typically speaking the oxygen sensor causes this code to appear. Here is the possible cause list from the manual for your car.
Possible Causes: Air leaks in intake manifold, exhaust pipes or exhaust manifold Base engine mechanical problem causing a lean A/F condition Fuel control Sensor is out of calibration (e.g., ECT, IAT or MAP) Fuel delivery component fault (clogged filter, low fuel pressure) O2 element is contaminated, deteriorated or it has failed Vacuum hose is disconnected, broken, leaking or loose
Hope this helps (remember to rating this answer ans leave us a testimonial comment). Thank you for using FixYa.
your car is probably running rough
its sucking air from the intake mininfold
is your intake maninfold plastic? but your veicle is defenetly having a vaccum problem
P0171 indicates a lean condition. The most common cause of this is a defective mass air flow sensor. Also check if any vacuum leaks.P0174 OBD-II Trouble Code
Service Bulletin Number: 48201
service engine soon lite on
check engine light on
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