Skip the auto shop - Our mechanics make house calls

Q: Codes P0171 and P0442 - is it a gas cap issue?

asked by on

Ran codes. Got code P0171 and P0442. I think the later could be a gas cap issue. The earlier appears to possible be several items, (Fuel Filter, MAS Mass Air Sensor, Idle Control Valve, ) I had CCVV and hoses replaced last Jan. 2016. at 100K. The light came on at around 107K.

My car has 109000 miles.
My car has an automatic transmission.

Hello. These "small leak" codes can be very frustrating! Both of these codes (P0171 - lean condition, P0442 - small evaporation system leak) are the result of an air leak in the engine’s air intake system. Causes can be leaks in the many rubber hoses in the air intake, leaking hoses from the secondary air pump, a fuel tank vent valve not sealing, a gas cap that isn’t tight as you noted, and so on. I would recommend having your Check Engine Light inspected by a mobile, professional mechanic, such as one from YourMechanic, to diagnose the problem, get an accurate assessment of damage and cost estimate for repairs.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: I drove without coolant for about 20 miles and the radiator fan is making a loud noise, how do I fix it?

There could be problems with your water pump, coolant lines, radiator overflow reservoir or the radiator that is causing a serious leak. Driving without coolant for any period of time can cause damage to your radiator or other cooling system...

Q: How do I tell if my power steering is going bad in my 2005 BMW x3?

Hi, thanks for writing in. Unfortunately, it sounds like your steering rack is done for, and needs to be replaced. This appears to be a wide-spread problem with this vehicle, without a recall or customer satisfaction program from BMW. If...

Q: How would i know that i need to replace the vanos?

The VANOS is a variable camshaft timing system that uses engine oil pressure to change the camshaft position. The VANOS solenoid is an electrically operated valve that diverts oil pressure to the correct devices under certain conditions. Usually the first...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.