So I took it and it came out with 2 errors.
one It's P0171 System too lean (bank 1)
P0171 OBD-II Trouble Code
Technical Description
System Too Lean (Bank 1)
What does that mean?
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.
Symptoms
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.
Causes
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 (K&N, etc.) can cause the MAF to become dirty if the filter is over-oiled
- There could be a vacuum leak downstream of the MAF sensor.
Possible Solutions
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
and the other one It's P0401 EGR Flow insufficient
P0401 OBD-II Trouble Code
Technical Description
Insufficient EGR Flow
What does that mean?
EGR stands for Exhaust Gas Recirculation. It is part of the vehicle emmissions system, and is used to reduce combustion temperature and pressure to control Oxides of Nitrogen. There are generally three parts to the EGR system: the
EGR valve, an actuator solenoid, and a differential pressure sensor EGR (DPFE). These things work together to deliver the correct amount of recirculation based on engine temperature, load, etc. The P0401 code means that OBD detected an insufficient amount of EGR.
Symptoms
You may notice drivability problems such as pinging (a.k.a. pre-ignition knock) when the engine is under load or the vehicle is at higher speeds. There may also be other symptoms.
Causes
A code P0401 most likely means one or more of the following has happened:
- The DPFE (differential pressure feedback EGR) sensor is faulty and needs to be replaced
- There is a blockage in the EGR (tube), most likely carbon buildup
- The EGR valve is faulty
- The EGR valve may not be opening due to a lack of vaccuum
Possible Solutions
In fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit.
- Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticable difference in RPM's with the EGR open
- Clean out the EGR valve and/or tubing to remove deposits
- Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model)
- Replace the DPFE sensor (with a good quality / OEM one)
- Replace the EGR valve