Check the alternator even if you suspect the car starter or battery may be the cause of the problem. The alternator can die with little or no warning but there a few signs to watch for: The "ALT" or "GEN" light illuminates on the instrument panel. The lights are dimmer than usual and may pulsate from dim to bright.
Alternators can go bad suddenly, or slowly over time. If your alternator is slowly going bad over time there are some warning signs you can look out for.
Signs of a Bad Alternator
Some of the things to look for are no-starting and trouble starting, dimming lights and problems with stereo system output. If your car starts but stalls when you're underway, your battery is probably not being recharged due to a faulty alternator.
An early warning sign that your alternator is going bad could be dim, flickering lights. This symptom could show up on any or all of your dashboard lights, reading lights, headlights or other lights. The alternator is supposed to provide the electricity for your car's lights.
When there is a bad alternator, your car will shut off while driving. This primarily happens as it affects the power supply. Alternator issues will make the engine lose power. However, the alternator will rarely fail.
If the vehicle randomly shuts off while driving or stationary, there is usually an issue with the engine. Typical patterns here are issues with the ignition system, mixture preparation or fuel. A known error here is that the vehicle was refueled with the wrong type of fuel.
Cars shouldn't shut off while driving, but when they do, the most common culprits are: A bad crankshaft position sensor. Other sensor issues in the engine. A faulty fuel system.
If you find code P0562, you very likely have a failing alternator (note that codes may vary by vehicle make/model/year). Get it checked out before it fails entirely. If you suspect a failing alternator but don't have a warning light, pop the hood and check the condition of the belt.
Age and use-related wear is often the reason behind a dying alternator. Engine oil or power steering fluid leaking onto the car alternator can lead to its failure. Prolonged idling while using multiple electrical accessories can prematurely wear the alternator.
It requires a good deal of energy to crank the car's motor, and if a battery is not replenishing its power properly due to a faulty alternator, it will become drained and ineffective. You will hear a clicking noise while attempting to start the car, and the engine will have difficulty turning over.
An effective method to determine whether it's your battery or alternator that's gone bad is to connect jumper cables from a running vehicle's battery to yours. After a few moments, try starting your vehicle. Once it's started, remove the jumper cables — if your engine stalls, your alternator has probably gone bad.
Most alternators will last between 80,000 and 150,000 miles — or about seven years. However, your driving habits and the area where you live could wear it out prematurely.
One of the most common problems you're likely to experience with an alternator is a failure in the bearings. There are needle bearings in the alternator that allow the rotor to freely spin inside the housing, and those bearings can break down over time as a result of exposure to heat and dirt.
An alternator typically lasts about seven years or about 100,000 to 150,000 miles. Some mechanics, though, say they typically see alternators last about 80,000 miles, or some cars will need it to be replaced after 50,000 to 60,000 miles.
Strong vibrations or water ingress are possible causes of bearing damage on alternators. But too much tension on the drive belt can also cause bearing damage or premature wear.
“When your only alternator fails at night, it's an emergency. Declaring buys you extra ATC attention and priority handling. That's exactly what you need, so don't hesitate. Then, land as soon as practical.
“Faulty or corroded battery cables or connections can also mimic a failing alternator or battery,” Mock says. A mechanic or battery technician can test the system to determine the cause of the problem.
Alternators can average anywhere from $100 to $350, depending on the model. In most cases, costs will average between $350−400 for the alternator replacement if no other parts need to be changed. Add another $20 to $50 to your bill if the serpentine belt has to be replaced as well.
Make sure your alternator's positive and negative terminals are clean. Put the multimeter's black cable to the negative terminal and the red cable to the positive terminal. Look for an ideal alternator reading of around 12.6. Start the car, and look for a reading of between 14.2 and 14.7.
But if the alternator isn't functioning properly and the battery dies, your car may eventually lose power and stall or completely shut off. So, can your battery die while the car is running? Absolutely. And oftentimes, this issue is caused by a combination of alternator and battery problems.
What should I do if my battery dies while driving? If your battery stops providing power while your vehicle is in motion, activate your flashers and head to the side of the road. The best option is to call for a tow.
The dash lights coming on and vehicle shutting down are, most likely, related to a charging system problem. It's fairly common for all the dash lights to come on with no alternator output, low voltage can cause unusual electrical issues. The alternator should have been tested at the time of battery replacement.
A failing fuel pump is one of the faults that can cause this. Other likely problems would be the battery, alternator, battery cable, wiring harness fault, crank or camshaft position sensor. The fuel pump may have been replaced because it was not turning on.
When your engine shuts off when you slow the car down its often as a result of a: Malfunctioning transmission. Low fuel pressure, dirty or defective fuel injectors, or broken fuel pump. Bad oxygen sensor or mass flow sensor.