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

asked by on

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
  1. Home
  2. Questions
  3. i have 3 code on my car P0431, P0174, P0305

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: Car won't start - 2004 Ford Focus

Hi and thanks for contacting YourMechanic. Check the battery cables for more corrosion and clean them up again. You may need to put backing soda and water mixture on the terminals to clean the corrosion completely off. Make sure that...

Q: Flooded car please help, potential damage? write off?

When the under vehicle got soaked and sat in the water the brakes tend to lock up after that if you had the parking brake on and then when you go to release it the rear drum brakes may stick...

Q: Cylinder 5 has a misfire.

Hi there. To determine if the injector is not working properly, either you can perform a cylinder cut out test on your injection system or you can swap your injector on cylinder number 5 with another cylinder and see if...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
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...