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Re: PO171 error code System too lean bank 1
Here are some possible causes, I would start with anything related to replacing the intake.
Air leaks in intake manifold, exhaust pipes or exhaust manifold Fuel control sensor is out of calibration Low fuel pressure (fuel filter clogged, pressure regulator failure) One or more injectors restricted or pressure regulator has failed O2 sensors contaminated, deteriorated or has failed Vacuum hose is disconnected, broken, leaking or loose
I had this problem. I had a code reader that I got from Costco for $35 and the error key read P2187 and the problem was "System Too Lean at Idle Bank". I talked to my uncle that was a mechanic and he said that it is usually a vacuum hose problem if there is an inconsistent idle as I was experience, especially is it was only at idle. I got a flashlight start the car up lifted the hood and looked at every rubber hose starting at the air filter. There was one that was loosely connect to the nipple, I pressed it down all the way and looked for more possible leaks but that fixed it. I started the car with the code reader twice, and it said "no codes found" both times. Try that first!
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code p 0171 refers to system too lean bank 1===causes --intake/exhaust leak---AIR system---MAF/VAF sensor---fuel pressure/ pump/ pressure regulator---injector/s---heated oxygen sensor (HO2S unit in the exhaust manifold or before the cat converter
If the engine is running well then consider replacing the HO2S unit as that reports to the ECM that then adjusts the mixture for that bank by altering injector amounts and timing
all the rest affect both banks but the code is bank 1 specific
code p0171 refers to system too lean bank 1===causes ---intake /exhaust manifold leak---ARI system--MAF/VAF sensor--fuel pressure /pump---injector/s---ECM
code po172 refers to system too rich bank 1===causes --intake blocked---EVAP canister purge valve---fuel pressure---EGR system---injector/s---HO2S
I believe this can be a bad O2 sensor error. It is a lean reading on bank 1. Also what can happen are intake manifold leaks, and stuck Intake manifold runners on 1 side of the engine. For the Manifold runners, these work like a gating system. Some Intake manifolds have 2 chambers, a low and high flow. When the gating runner sticks in the high flow position, too much air enters the engine on Bank 1 during idle or low rpm. Manifold leaks. Use a spray water bottle and with the engine running, spray the seams of the manifold. A leak will change rpm or stall the engine. Hope this helps you.
p0171 is the code for system too lean bank 1. possible causes intake/exhaust leak--air system maf/vaf sensor-fuel pressure--manifold regulator/ pump--injectors Ho2s Check for leaking rubber hoses. Have a fuel pressure test done and replace the sensor.
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.
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
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