Skip the auto shop - Our mechanics make house calls

Q: Battery/Alternator - 2008 Toyota RAV4

asked by on

One day I noticed a different sound coming from engine. It was a low hum sound. It was not super loud or distinct I just noticed it was unusual. Not long after battery light came. The next few times I would start the car sometime I saw the battery light and heard the noice-others time the car was working as normal (no warning light/noise). I usually drive my car for short distances. 10-15 minutes trips are normal so maybe the battery is not getting enough charge. The car was operating normally and I ran some errands. On my way to my second stop, the power steering dropped out. Many warning lights turned on - such as VSC, battery, check engine, oil light and steering. This leads me to believe it is an issue with the alternator. I parked the car and turned the engine off. The car would not start again. I used a battery jump to recrank car. The car would start but would not stay on. I attempted this a couple of times. There is lots of corrosion on the battery also.

My car has 90000 miles.
My car has an automatic transmission.

A: The battery and charging system should be e...

The battery and charging system should be evaluated first. However, if your battery is more than 5 years old, I would simply replace the battery outright before doing further diagnostics (which are still needed). Batteries are actually critical components of vehicles, even much more so these days due to the proliferation of electronics in vehicles, and the fact that some components are very sensitive to voltage disturbances.

To work properly, the battery has to not only supply the right voltage, but it has to supply enough current to all the devices in your car (ignition, HVAC, lights, etc.) without excessive voltage drop. So you could have an old battery that has problems. But even if you "simply" replace an old battery, the mechanic will check the output of your charging system of which the alternator is just one component. So, initially, yes you appear to have an electrical problem and the initial points of concern are the condition of the battery and whether your charging system is functioning properly.

If you would like to have this resolved, consider YourMechanic, as a certified technician can come to your car's location to diagnose the charging system and have this problem addressed.

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

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!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: Car switched off but did not start when I tried to restart

Hello. First of all, rotating the engine counterclockwise could very well cause the engine to "jump time", and cause engine damage. The timing chain tensioner is not designed for this pressure, and can allow the timing chain to jump one...

Q: How do I adjust the manual anti-glare rearview mirror?

If your vehicle is equipped with a manual anti-glare rear view mirror, you have the means to adjust it to account for bright lights behind you. The glare from headlights behind you at night can be blinding, reducing your night...

Q: Wheel bearing going out

Hi there. A faulty wheel bearing will generally cause a growling noise similar to a chopping or cupping wear on the inner or outer edge of one or more tires. To determine this, the tire on the suspected wheel of...

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 Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
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 P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...