Q: Failed emmissions test

asked by on

I went to get my emissions checked today and my car failed the test. The hydrocarbons read 9.0 pm which was off the chart and the CO% was 361. Do you know if new plugs and wires would bring down the numbers enough to pass the test? Is there anything else I could replace to help pass the test?

Hello. If the plugs and wires have not been replaced for several thousand miles, then replacing them may indeed help lower emissions levels. New plugs and wires can help produce a stronger spark, which will result in a cleaner burning fuel mixture. However, due to the excessively high hydrocarbon levels, this alone may not be enough for the vehicle to pass the test. A full tune-up, along with a thorough inspection of the ignition and fuel systems, may help lower emissions levels further, perhaps enough for the vehicle to pass. I would also recommend checking the condition of the catalytic converter, as a faulty catalytic converter can cause the vehicle to produce higher emissions as well, particularly CO. If you need help, a certified technician from YourMechanic can replace the catalytic converter for you.

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. Failed emmissions test

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 cannot locate the solenoid vent valve in my car.

Hi there. The purge control valve that you are looking for is located next to the valve cover and between the engine and the firewall to the front of the engine area. The valve should have vacuum type hoses attached...

Q: 01 Dodge Ram jerks when taking off, bogs down , when coming to stop it feels like it wants to go but dies

Hi Frank. Thanks for contacting us today. Typically an issue like you are describing is caused by a fuel restriction or inability to correctly mix air and fuel together. Some of the usual suspects include a vacuum leak, mass air...

Q: Vibration on startup - 2013 Ford Focus

Hi there. From the description you have given, a tune-up may be in order. Short trip driving is harder on the engine, than long trip driving. Based on the low mileage, it is not due for the tune-up according to...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
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...
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.