Q: i have 3 code on my car P0431, P0174, P0305

asked by on December 02, 2016

The car have very loud noise when drive above 30 mile/hour sound like muffler have exhaust leak, but bring to muffler shop and they check and found no exhaust leak, they said maybe possible is motor mount crack or damaged, for code P0174 they said possible boot leak as the boot near MAF sensor is wrap with tape, already change the ignition coil on cylinder no 5 but the code is keep coming back after 1month

My car has 157055 miles.
My car has an automatic transmission.

Noise in exhaust systems occurs due to leaks as well as internal failure of the baffles in the muffler or resonator. So, just because there are no leaks, doesn’t mean the exhaust system will be noise free. An [engine/exhaust noise diagnostic(https://www.yourmechanic.com/services/noise-from-engine-or-exhaust-inspection) could be performed. The motor mount can be visually inspected and tested; they should have been able to give you a conclusive answer as to the condition of the motor mounts. With regard to Diagnostic Trouble Code P0174, if there is tape applied to repair the rubber air intake boot, then the boot does have to be replaced as part of any diagnostic for Code P0174 simply because leaks at an intake boot are a known cause of Code P0174. Once an obvious fault is found in a diagnostic, such has to be repaired in order to complete the rest of the diagnostic and indeed such repair may conclude the diagnostic because the torn boot might the faulty component that caused the Code to set. Once the rubber air intake boot is replaced, if Code P0174 recurs, additional possibilities have to be considered such as: other air leaks (other than the boot) after the mass air flow (MAF) sensor including the intake manifold gasket, a dirty or faulty mass air flow sensor, a faulty oxygen sensor, incorrect fuel pressure, leaking positive crankcase ventilation (PCV) valve, clogged exhaust gas recirculation (EGR) port, and leaking brake booster.

Trouble code P0305 relates to cylinder No. 5. The coil is only one possible fault that might set this code. The following additional components have to be considered or tested: the spark plug; spark plug wire or plug boot which could be leaking to ground; valve cover could be leaking oil into the spark plug holes and shorting the spark plug to ground; and power supply to the ignition coil. Trouble Code P0431 typically sets if there is an exhaust leak, the catalytic converter is not working and/or an oxygen sensor is failing or has failed. What I recommend you do is get a check engine light diagnostic. At the conclusion of that, the Mechanic will let you know specifically which components are faulty, thus causing these codes to be set, and itemize for you the required repairs and the cost. Please let us know if you have additional questions or concerns.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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

04 jeep liberty 3.7 cranks but does not start

If the engine cranks at adequate RPM, be sure there is adequate fuel in the fuel tank and that the fuel is not old. Download any OBD-II trouble codes that have been stored and examine those codes for diagnostic clues....

Cranks great will not fire up - 1992 Mazda 929

The antenna wire should not be connected to anything that would cause the car to not start, especially if it is getting power to crank. I would suggest checking to see if the spark plugs are getting fuel to them....

My compressor went out. Will that cause my engine to not operate?

Hello. If you have an engine that is cranking but not starting, then you need to look on dashboard to see if the theft light is flashing first. If it is, then try a different key to see if that...

Related articles

The Best Used Cars to Buy If You're a Personal Assistant
As As a personal assistant, you have a lot of demands placed on your time. Often it’s important that you be able to get around town quickly, running a ton of errands, picking things up here, dropping them off there,...
The Best Used Cars to Buy for Occasional Drivers
Not Not everyone relies on their car on a daily basis. Maybe you aren’t the type that deals with a daily commute, and running from here to there constantly. If that’s the case, you may be looking for a car...
2012 Honda Odyssey vs. 2012 Mazda 5: Which One Should I Buy?
Passenger vans may be one of the most maligned classes of vehicles. From being called "Mom-mobiles" to being mocked extensively by those who have not experienced the comfort and ease of getting into and out of a van, vans just...