Skip the auto shop - Our mechanics make house calls

P0174 OBD-II Trouble Code: System Too Lean (Bank 2)

Check Engine Light

P0174 code definition

System Too Lean (Bank 2)

What the P0174 code means

Code P0174 indicates that there is a lean condition detected by the Engine Control Module (ECM). A lean condition will be created if there is too much air, and not enough fuel, in the air fuel ratio (AFR). The ECM is designed with the capability of adjusting a lean condition back to normal, but only in small to mediocre amounts. If the air fuel ratio requires more compensation to return to normal than the ECU is capable of, code P0174 may set.

What causes the P0174 code?

  • An air leak after the mass air flow (MAF) sensor, such as a torn intake boot, or bad intake manifold gaskets

  • A dirty or faulty mass air flow sensor

  • Faulty oxygen sensor

  • Incorrect fuel pressure

  • Leaking positive crankcase ventilation (PCV) valve

  • Clogged exhaust gas recirculation (EGR) Port

  • Leaking brake booster

What are the symptoms of the P0174 code?

  • Increased fuel consumption
  • Check Engine Light will come on
  • Rough or high idle
  • Decreased acceleration
  • Engine stalling

How does a mechanic diagnose the P0174 code?

  • Performs a fuel pressure test
  • Checks the intake system and vacuum lines for leaks
  • Inspects the valve cover for worn hoses or leaks
  • Inspects the PCV valve
  • Tests the mass air flow sensor with a scan tool or multimeter
  • Tests the related oxygen sensor with a scan tool or multimeter

Common mistakes when diagnosing the P0174 code?

  • Replacing a component without first deeming it bad through testing
  • Failing to check the intake system for tears or leaks

How serious is the P0174 code?

Generally, a lean condition is not that serious. However, be aware that there is a possibility of the lean condition being caused by a leak in the intake system. Leaks in the air intake may allow particles to enter the engine, which may be damaging.

What repairs can fix the P0174 code?

Additional comments for consideration regarding the P0174 code

Be sure to check the intake manifold and vacuum lines for leaks.

Need help with a P0174 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Post a question and get free advice from our certified mechanics.

ASK A QUESTION

More related articles

How Long Does a Fuel Filler Neck Last?
Getting gas from the pump to your gas tank is the only way to keep a car going. The fuel filler neck is a metal tube that is welded to the...
P0121 OBD-II Trouble Code: TPS "A" Circuit Range Performance Problem
P0121 code definition Throttle Pedal Position Sensor/Switch (TPS) A Circuit Range Performance Problem What the P0121 code means P0121 is a generic OBD-II code which indicates that the Engine Control...
How to Buy Fuel Treatments
Adding a fuel additive to your gas tank when you fill up is one way to clean vital engine parts of deposits, improve the performance of your engine,...


Related questions

Q: Car isn't shifting when pedal is all the way down and is slow.

Your engine management system is going into "limp mode" when the Check Engine light is illuminated, reducing engine power, and quite likely, leaving your automatic transmission in 2nd gear. This is why you are experiencing greatly diminished performance. Turning your...

Q: My MIL light came on and stayed on for about 2 weeks then went off

Hey there. When the computer detects a problem it will turn on the Check Engine Light and stores a code in the memory. If the problem is intermittent and only happened that one time then after a certain amount of...

Q: Codes showing: P0171, P0420, P0174

Hello. These diagnostic trouble codes are an indication that there could be a problem with the oxygen sensor or that there is a vacuum leak. It is possible that the vacuum leak is located in the intake manifold. These codes...