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P0171

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P0171 OBD-II Trouble Code: System Too Lean (Bank 1)
P0171 code definition System Too Lean (Bank 1) What the P0171 code means The P0171 code means that, on the first bank of the engine, the fuel system is running weak...

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Question
Error code P0171 and P0174
The high positive long term fuel trim suggests a vacuum leak and/or inadequate fuel delivery. But there are other causes that have to be evaluated as well: bad oxygen sensor(s); dirty MAF sensor; stuck open EGR valve; weak fuel pump;...
Question
I have codes P0151, P0171, and P0174. I have changed out my O2 sensor, but now I have all these codes
Hey there. The codes you have downloaded simply relate to malfunctions in the "engine management system." It appears codes were set for oxygen sensor voltage out-of-range, possible EGR (exhaust gas recirculation) problems such as a blockage, and a generic code...
Question
Too lean in bank 1 and bank 2
Hi and thanks for contacting YourMechanic. When the engine becomes too lean, then combustion chamber becomes very hot causing the head gasket to burn, valves begin to burn, and the rings being to seize up. Check the camshaft sensor and...
Question
Car is jerking back and forth. P0171 and P0172 codes are on.
Hello. These symptoms suggest something is causing big swings in the fuel mixture when this occurs - quite possibly the O2 sensors (pre-catalytic converter - 2 of them). P0171 is a "lean mix" warning, and P0172 is a "rich mix"...
Question
OBD-II codes P2195 and P0171 appear
P2195 and P0171 occur when the engine is running too rich (too much fuel relative to air charge) and the engine feedback system is unable to compensate. The "how can you fix this" depends on which component(s) in the system...
Question
I keep getting OBD-II codes P0171 and P0174
Since you have codes that both banks are lean then the problem will most likely be from air entering the intake manifold after the mass air sensor. The idle air control valve should not have any air leaks from the...
Question
Carbon canister making a loud hissing noise.
Hi there. The loud hissing noise could be caused by a split vacuum hose or a loose hose. Follow the hiss to make sure it is the canister and not a separate hose. The code stored for the Check Engine...
Question
My car has recently been taking about 5 minutes of cranking to start - do I need to replace the engine?
Before resorting to removing the engine, have a certified technician properly diagnose your hard starting condition. Hard starting or a long cranking situation can be caused by a number of things. The "system too lean" code can contribute to a...
Question
My truck is giving codes P0171 & P0174
Hi there. If the engine is running lean, then there could be a plugged fuel filter or a faulty fuel pump with loss of pressure. If the pressure is dropping after 20 to 25 minutes, then there could be a...
Question
Error codes P0171 and P0374
Hello. These issues can be caused by a few things. From the codes it sounds like there may be an issue with the fuel system. It may also be an issue with the air intake system allowing too much air...
Question
The gasket is deteriorated in the intake manifold gasket
If the gasket does have to be replaced it is replaced as a "whole". There is no partial intake manifold gasket. Please note that the code you are writing in about, Diagnostic Trouble Code P0171, can set for many reasons...
Question
Error code P0171 and P0374
Hi and thanks for contacting YourMechanic. If the vehicle went into limp mode, then the computer is making this happen to prevent the engine from any damage. Check the camshaft sensor for proper timing to the camshaft. Look at the...
Question
Check engine light
Hello. P0171 is the trouble code for a lean condition at bank 1. This can be caused by a wide variety of issues, primarily issues with the engine management or fuel systems, and therefore can sometimes be difficult to diagnose....
Question
P0404, P0405, P0171, P0174
Hello. Thank you for writing in. Due to the p0405 code, you will want to start by replacing the sensor. This is typically easier and cheaper than replacing the EGR unit all together. If the light continues to illuminate, then...
Question
Intake air flow leaking. What makes this happen?
Hi there. When having the code P0171, the fuel system is too lean. This could be the fuel pump is not working, the fuel filter is dirty or plugged, or the injectors are plugged or not working properly. Check the...
Question
I failed a smog check with the codes PO171 & PO174, saying the system is too lean on the bank 1 & 2. Can you tell me what the problem is?
Hi there. When the two codes P0171 and P0174 come up for a lean system on both banks of your engine, then either all of the fuel injectors are not working properly or your fuel pressure has dropped. Check the...
Question
What could be the cause of code P0171
PO171 occurs when the fuel mixture has gotten so lean that it is out of the range that the ECU can compensate. It can be accompanied by poor idle quality, weak performance and even stalling. While Oxygen sensor number 1...
Question
I have a code P0171 and needs repairs.
Hi there. The code P0171 is caused by the engine getting too hot and not having enough fuel to burn. Check the fuel injectors, fuel pressure, and the fuel pump to see if they are working properly. Since the vehicle...
Question
Got a trouble code P0171.
The purpose of the No. 2 sensor is to monitor the efficiency of the catalytic converter. Consequently, if everything is functioning correctly, the No. 2 sensor is supposed to report a constant voltage. If the No. 2 sensor waveform mimicked...
Question
Periodically vehicle runs rough at idle.
Hi there. Most of the codes that are coming on are for a misfire on cylinder number 3. Check the spark plug and wire on cylinder 3 and see if you are getting a good spark. Then check the fuel...

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