What causes lean fuel code?
The lean condition can be caused by a vacuum leak, which introduces more air into the air-fuel mixture, or by a weak fuel system, which does not input enough fuel into the air-fuel mixture.
Can a bad O2 sensor cause a lean code?
So, an oxygen sensor failure can lead to incorrect readings of exhaust gasses. As a result, the faulty sensor can cause, a too rich or too lean condition. Any fuel that leaves the combustion chamber unburned; will enter the exhaust system and light-off when it reaches the catalytic converter.
What causes the p0171 code on a Subaru Forester?
Vacuum Leaks – With the Subaru Forester, one of the most common cause for the P0171 code to show is a vacuum leak. Take a look around and see if you can find the vacuum leak. Here’s a great YouTube video on how to find a vacuum leak. Oxygen Sensor – The P0171 codes is thrown when the oxygen sensor (s) do not register enough oxygen in the exhaust.
Why is my p0171 system Lean code not working?
Change the plugs and oil about a month and a half ago and got a maf sensor error and get a P0171 system lean code after resetting the ECU. I’ve been troubleshooting since then but can’t seem to get the P0171 ironed out. The cel only pops at idle and the car runs great through the power band. Here’s what I’ve already done.
What does the p0171 code on bank 1 mean?
Code Definition. P0171 – System Too Lean (Bank 1) What does the P0171 code mean? The P0171 code means that the Oxygen (O2) sensor on bank 1 recognized a too lean mixture to correct it. The Oxygen O2 sensors have the ability to correct a fuel mixture of +-15%. If it needs to correct the air-fuel mixture more than that, the P0171 code will be stored.
When does the front O2 sensor Register p0171?
P0171 is triggered when the front O2 sensors recognize a lean mixture. It can both be a short-term lean mixture or a long-term lean mixture. If it’s a short-term lean mixture the fuel mixture is often very lean. If it’s a long-term mixture, it can register the code because of a small notice of lean mixture over time.