Q: Check engine light in code P0418

asked by on October 07, 2016

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?
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

My Chevr HHR (2006) has milky oil, and white smoke puffs out of the dipstick tube. The car doesn't overheat,and the heater works.

Check for any change in coolant level in the overflow reservoir. If no change over, say, 500 miles, you simply have a high level of condensation because there is absolutely no other source of water to the engine. You can...

Choice of brake rotors and pads front and rear.

Hi there. When it comes to buying brake pads, to be completely honest, almost every aftermarket part made today will be fine for your application. In regards to personal preference, I'm a fan of OEM brake pads and rotors -...

Car squealing

If the pulley moves back and forth, this would suggest that it is loose. Depending on which pulley it is, this may cause the belt to squeak if it moves back and forth due to the amount of force being...

Related articles

P2629 OBD-II Trouble Code: O2 Sensor Pumping Current Trim Circuit / Open Bank 2 Sensor 1
P2629 P2629 code definition The P2629 trouble code detects a problem with the voltage signal from the oxygen sensor pumping current trim circuit of sensor 1 in bank 2. What the P2629 code means P2629 is a standard OBD-II trouble...
P2609 OBD-II Trouble Code: Intake Air Heater System Performance
P2609 P2609 code definition A P2609 trouble code indicates that the PCM has detected abnormal voltage readings from one or more of the intake air heater circuits. This particular trouble code is most often associated with trouble codes P2604, P2605,...
How to Replace Your Serpentine Belt
If If your engine squeals in the morning when you first start it up, take a look at your serpentine belt under the hood. Any cracks, glazed areas, or visible threads mean that you need to replace it. Let it...