Q: My check engine light just turned on mid drive and I began noticing a high pitch hum only while accelerating...possible issues?

asked by on January 31, 2017

The car drives fine no real stand out issues other than the faint hum. Does not do while in park or in low gears. Starts just as I shift into last gear around 3rpm and 45mph. Sound gets higher in pitch the faster I go making it less noticeable.

My car has 127000 miles.
My car has an automatic transmission.

Alternator Replacement $149.30 - $1391.75 Get a Quote

Hello, There are a number of possible causes for creating a humming sound as you describe, however the most common that would also be correlated to RPM change would the a failing alternator. When the alternator is not working properly, this may result in the battery quickly losing charge and the car losing all power as you have described. You may also notice a whining sound as a result of the bearings inside the alternator begin to fail. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your charging system.

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

What others are asking

I have to jump my car repeatedly.everytime I try to start my car no matter how long it was running for.altenator belt still spins.

If your car will not stay running after jump starting then the charging system is not working and may need an alternator and may even also need a new battery. If you need help with this, I recommend having a...

Car loud during acceleration

If the engine is making a lot of noise when you accelerate then that can be a sign of engine failure or something that is loose. A description of the noise would help. If it is a banging then it...

Timing belt and water pump replacement

The replacement of the water pump was your choice not the dealer. If you requested the water pump to be replaced at the same time the timing belt was replaced to save in labor so you do not have to...

Engine sputtering and manual gear-shifter is getting stiff.

Hi there. It's possible that the shifting issue could be related to the clutch, but that seems more like a gear linkage issue. The engine vibration is most likely not related; and could be caused by a damaged vacuum line...

Rough idle with ac and defrost on

A rough idle may be caused by many different things such as low fuel pressure, low voltage to the fuel injectors, dirty fuel injectors, a vacuum leak, a faulty Oxygen sensor or a dirty or failing idle air control valve....

How do I view the instantaneous fuel consumption?

The instantaneous fuel consumption feature is displayed on the multi-information display, and shows you the fuel economy that your vehicle is achieving at any given moment. To view the instantaneous fuel consumption, press the display button on the lower left...

When your power steering line that runs to the rack is stuck and will not turn with a wrench at all how do you remove ? 2004 Kia R

I would recommend first removing the power steering pump. Then pull the power steering pump away from the engine as far as the connected power steering line will allow. Then I would use a torch on the flare nut of...

How do I adjust the cross rails?

If your vehicle is equipped with a roof luggage carrier, it’s a convenient way to expand your cargo carrying capacity. However, you’ll need to make sure you have the cross rails positioned correctly for your load. You can slide the...

My 2004 Chrysler PT Cruiser is overheating

Hi there - there are a couple of possibilities. The simplest and most likely possible case, based on the recent thermostat replacement, is that the cooling system was not properly bled of air pockets, and is boiling coolant inside the...

Related articles

A Buyer’s Guide to the 2012 Toyota Tundra
While While Toyota hasn’t been in the business of manufacturing larger pickup trucks as long as the likes of Ford, Chevy, and Dodge, the Tundra is most definitely a force to be reckoned with. This full-sized pickup has comparable payload,...
A Buyer’s Guide to the 2012 Toyota Prius Plug-In
Toyota Toyota definitely isn’t sitting on its laurels where hybrid cars are concerned. To compete with other electric cars like the Chevrolet Volt and the Ford Focus Electric, the 2012 Toyota Prius Plug-In gives car buyers a higher-mileage vehicle with...
2012 Toyota Prius vs. 2012 Chevrolet Volt: Which One Should I Buy?
While these two vehicles are both certainly cost-effective to drive, they can be difficult to compare due to the Prius’ entry in the mid-size category and the Volt living squarely in the compact car category. Both of these vehicles are...