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!
  1. Home
  2. Questions
  3. Codes P0171 and P0442 - is it a gas cap issue?

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: Radiator blown vehicle shuts off immediatly

Your vehicle has a coolant level sensor but that sensor does not function as an "interrupt" device. All it does is report if the coolant level is too low. The cause of the shut-down could vary from sensor damage (sometimes...

Q: Service Engine Soon light going on and off.

Sometimes a code will set under certain criteria and while your driving the criteria goes away and the computer recognizes it and it turns the light off, this is normal operation, but that the light comes on it should save...

Q: No power. Only uses bank 2 to fire

Hi there. It would be helpful to know the year of the car in this case to supply the most accurate information. If it were the map sensor, then it would affect all cylinders. Try checking the spark plugs for...

Related articles

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...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...