Q: Check engine light in code P0418

asked by on

Car running rough and cuts off sometimes when almost stopped check engine light code P0418 secondary air injector relay a malfunctuon we tested some things on the blazer checked the air pump fuse it was good replaced the relay and tested the air pump by the battery but then when you hook it back to the car it doesn't turn on and the connections look fine replaced the idler pulley but still needs serpentine belt

My car has 107000 miles.
My car has an automatic transmission.

The air pump fuse is a 30 amp fuse that powers the pump. The "trigger" for the relay comes from the ignition switch, through a 10 amp fuse. Have you checked to see if the "trigger" wire to the relay is going to 12 v? If not, check the 2nd fuse and ignition switch path.

I would recommend having a certified technician, like one from YourMechanic, perform a rough idle inspection, and check your serpentine belt, to diagnose these issues, provide an accurate assessment of damages, and estimate the cost of repairs. YourMechanic can dispatch a mobile, professional mechanic to your location for diagnosis and repairs.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 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. Check engine light in code P0418

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: Truck ac pressure too high after repair

An overcharge of either refrigerant oil or refrigerant can cause excessive system pressures. If the wrong refrigerant oil is installed that might contribute to excessive pressure. Check low side pressure. If low side pressure is too low, while high side...

Q: Fuel connector disconnected from fuel pump

It does sound like your Chevy Blazer is experiencing some serious fuel pump issues. Your Blazer is set up in a way that the fuel lines leading to the rest of the car are connected to the fuel pump with...

Q: Check Engine Light with code P0740

There are a number of symptoms that may accompany a P0740 code, it may be that your car will stall at stop lights, or have trouble shifting, or you may not notice anything at all except your gas mileage is...

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...
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...