Skip the auto shop - Our mechanics make house calls

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.

A: The air pump fuse is a 30 amp fuse that pow...

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 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

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 want to put a straight pipe with no muffler on my 2005 Chevy Silverado and keep the catalytic converter

Removing the muffler will not decrease the horsepower, but instead it will create less back pressure on the engine, making the engine breathe a little more. Make sure that the exhaust will not be too loud for the zoning laws...

Q: Dies unless pressing gas pedal

Hi There, This is usually an indication of a fuel supply or low fuel pressure problem, which may be a result of clogged fuel injectors, a bad fuel pump or possibly a faulty fuel pressure regulator. Any of these may...

Q: Code p0420

Hello. P0420 could be due to a variety of faults including even a fuel pump that is not supplying sufficient fuel, causing a lean condition, and hence "fooling" the O2 sensors (pre and post) as to the status (i.e., efficiency)...

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 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...
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.