I'd drive it to an autozone or like place to have the alternator checked. I'd guess it is not charging your batteries, hence they die and so does the engine (ECU needs 12V constant).

If you have a voltmeter check your battery, it should have at least 12.7V first thing in the morning.

 

A little update: I checked the voltage on the battery this morning and it was around 11.6, I know that's low so I went ahead and tried jump starting the car. The car actually tried starting but wouldn't crank, this time no machine gun noise, just a couple slow crank noise but if I held the key in the start position for too long then the machine gun noise comes back.

Is my problem a starter or alternator issue?

 

If money is an issue, any auto parts store will test your battery, alternator and starter for free.

Also, I was able to buy a genuine DENSO remanufactured alternator for my 2010 Camry on the Walmart website for only $198, with no core charge. I’m sure if you look around you can probably find a genuine Denso alternator for a lower price.

On the 4-cylinder Camry, changing the alternator and the starter is very easy.

Is your vehicle a 4 cylinder or V6?

 

I would confirm that there is actually a vendor who has a remanufactured Denso alternator. If you ascertain this is a legitimate offer, go for it. It's hard to find remanufactured Denso anything right now.

 

You have an old, weak or worn out battery. It is not fully charged, even if "New", it could be old and discharged. You need to charge your battery fully before messing with this and certainly don't try jump starting a weak battery or you could damage an expensive ECU with the system voltage down to 4 - 6 volts, don't do that.

With a fully charged or new battery at 12.8 V or higher, then the car will likely start; then use your meter to measure the voltage at the battery terminals, this may give a clue about the alternator, but a current measurement is really needed to determine.

A weak or worn out battery can cause the alternator to run at excessive currents to try to maintain the system voltage for a long time (like when the battery light was flickering while driving all that time) and damage the alternator. One thing leads to another. The warning lamp on the dash was trying to tell you there is an issue that needed attention.

Lead acid batteries must be kept fully charged all the time; they will self discharge from 3 to 8% per month if left sitting, and will be permanently damaged and lose capacity due to sulfation of the plates. During the pandemic New batteries sat on the shelf and became worthless, but were still sold as "New".

 

Possibly the battery is weak, especially if this is the original battery. A weak battery can overwork the alternator and damage it, or just blow out the alternator fuse. Running off just the battery will run it flat and the engine will quit, just like happened to you. First check the alternator fuse. If it's bad, replace it and say a prayer that the alternator is still good- it will have to be tested. The battery needs to be charged and load tested. If that battery lasted from 2010 to the present that says it was of pretty good quality- brand and model number. There will be sticker shock if you need a new battery. They cost twice as much now as they did in 2016 when I replaced mine and there really is no reason for the price increase since the quality did not change.

 

Thank you guys for the replies and suggestions!

Now that I think about it, this car was sitting in the backyard for a couple years without driving. I have only been driving it for about 6 months since then without problems.

This is a 4 cylinder camry, I'm glad to hear that there are pretty cheap options. I did check the alternator fuse and it's still good

Also to note, even though the battery was reading low around 11 volts, I tried cranking the car and checked the volts again and it tanks to around 5-8 volts. I know that's not normal but would that still be a sign of a weak battery problem? or something else?

Anyways, I will start by getting my battery charged and then give you guys an update!

 

After you get the battery fully recharged from an external battery charger, take the car to an auto parts store like Autozone. They will bring a machine out to the car and check the battery and alternator for free. You most likely have a bad alternator. From your description your alternator was probably not recharging the battery and you were driving on whatever power the battery had, until it's power was completely drained and the car died. The multiple rapid clicking you are experiencing when trying to restart the car is indicative of a weak battery or corroded connections at the battery, the starter, or a ground connection. My vote is for a defective alternator.

Mike

 

Hello I’m new here, I have 4th gen Camry 2.2.

I have my money on the alternator for sure because the battery is draining, this issue is 100% to that. Corrosion around the battery studs won’t really cause draining problems just starting ones.
You should test it, when you turn it on again …disconnect the ground cable. If the engine turns off, well there you have it… your alternator is bad.
There’s also a light chance it could be some loose connections but it more likely to be the alternator.

Now if it doesn’t, then the battery is the issue.
Hope this helps, cheers ! 👍🏽

 

Don't listen to this bad advice. Never disconnect the negative battery terminal while a car is running! This is stupid advice which will be an expensive mistake.

When current is flowing in a circuit, it is following the path of least resistance to complete it's path.

If you disconnect a ground connection in an active circuit, then bad things happen.

"If you do not have a current path, then one will be provided for you"

The current will create a path back to the source and will arc and destroy anything in it's way, usually thru components in the ECUs.

 

Give us an update after you get the vehicle properly diagnosed. I want to know the fix.

 

Listen to kenny-bob323. Never disconnect the battery while the car is running. This was an OK test in my youth many many many years ago. Back then cars did not have the sophisticated electronics they have today. Disconnecting the battery while the car is running can create voltage spikes that can destroy some of these sophisticated (expensive) electronics.

Mike

 

Listen to kenny-bob323. Never disconnect the battery while the car is running. This was an OK test in my youth many many many years ago. Back then cars did not have the sophisticated electronics they have today. Disconnecting the battery while the car is running can create voltage spikes that can destroy some of these sophisticated (expensive) electronics.

Mike

Ok, I was actually gonna try that when I got the chance but thanks for warning me haha.
Since I can't drive anywhere I ordered a home battery charger and I've been letting it charge since my previous post.

My battery is close to 13 volts, I will install it tomorrow morning and give you guys an update.

 

Update: My battery was charged up to about 13.8v, I installed it and started the car, the car immediately died. I cranked it up again and revved the engine and it stayed on this time. The battery light is still on, my headlights, radio and ac are all turned off.

I checked the voltage of the battery and it dropped to around 12.7v to 12.8v and stayed around there at idle.
I turned on my radio, headlights and heat, checked the voltage again and saw that it's reading 11.2v.
I turned the headlights and radio back off, checked battery again and it stayed around 12.2v at idle.

So, maybe bad alternator? Or bad ground wire somewhere? I checked all the ground wires that went under the air filter, not sure where any others are.

 

Update: My battery was charged up to about 13.8v

Depending on the type of battery, it sounds like it didn't get Fully Charged.

The charging should run up to 14.4 V and hold there for sufficient time to de-sulfate the plates and fully charge the battery. Then when taken off the charger and left to sit for several hours, the open circuit voltage can be measured to give you some idea of the battery condition. At 13.8 the charger was still trying to charge the battery. A so-called smart charger is supposed to automate this process by going up to 14.4 and then backing off to a float voltage.

From your latest test data it does appear that the alternator is not able to charge the battery, not sure if it is a bad connection, fuse or alternator itself.

A clamp-on current probe on the positive cable from the alternator to the battery would show if the alternator is making current or not; Or, if the battery is defective then the alternator voltage might be pulled down due to very high current being dumped thru a defective battery. You need both voltage and current to evaluate an alternator.

Fully charge the battery if possible. If it will not reach the 14.4 while charging then that is a clue that the battery is no good. Then load test the battery on the bench or at an auto parts store.

If the car runs and you trust it will make it, then taking it to an auto parts store that will test both battery and alternator seems like a good idea. Be prepared to buy both. Be sure to disconnect the battery when replacing an alternator or doing any engine work under the hood.

 

There is a 7.5 amp charging fuse in the underhood fuse box, I have seen them slightly corroded and just removing it and replacing fixed it. I used to live in road salt and salt air. Hey, takes a minute. You can disconnect a battery with the engine running, just have the headlights on and heater fan on to load the alternator.

 

You can disconnect a battery with the engine running, just have the headlights on and heater fan on to load the alternator.

Wow this is really bad advice, have you ever done this with a digital computer controlled car?

What could definitively be proven or disproved by taking such a potentially expen$ive risk?

i have a pile of blown components (transistors, diodes, capacitors, etc) on my workbench from repairs i've done on numerous ECUs over 40 years from folks who have done stupid things like this and mishandling jumper cables too.

 

Another little update:
I placed my positive volt meter probe on the positive battery post and placed the negative probe onto the alternator case/mount and I was getting a reading of my battery power which is around 12.6v now.
I placed the negative probe onto the engine block and was getting the same reading.
I was watching some videos on how to test your alternator and from what I can understand that means there's a bad ground somewhere? Or I am doing it all wrong.

 

we typed at same time.....

1..... yes trickle charge battery.... 13V you got on meter, the next morn will be 12.6 to .8 V
12.4 to 12.8 after resting will go down in V some is a full charge battery.

2..... have a cheap multi meter ready.... get one from Harbor Freight for $6 or borrow one.
Once you start the car with charged battery..... put meter on DC Voltage at the 20V selection and put on the running car on the battery terminals. Lights off, radio off, defrost off all off. Should measure 14.4V or close and that will show the alternator is charging. IF you only have the 12.6V of the battery, you do not have alternator charging.

Could shut off car now.....
Alternator is Faulty?
Ck the connector.... mate & unmate a few times
Ck Ground To Alternator Ground..... measure resistance from Battery Neg to the Alternator Body.... should be 1/2 ohm or much less and just verifies we have good ground to alternator

Start car again......
Ck the charging voltage on the battery + - terminals again. Looking for Alternator Charging at 14.4V or so
If not faulty alternator..

Will second getting the Denso OEM type alternator.
Can remove the alternator .... and any auto store can test the alternator on the bench tester.... Free to test
Ck you fuses again.... look in manual to see if second fuse location (s) you may have missed.

 

I spent the afternoon reading through these forums and couldn't find a solution, hope someone can help out. I'm trying to troubleshoot this before I spend all my money on an alternator.

My battery light has been flickering on and off only while driving the past few weeks. I haven't had any problems recently: car starts fine, no dimming lights, radio works etc.
Yesterday the battery light turned on and stayed on and solid while I was driving on the highway, a few minutes later all of the lights on my dash turned on, a second later my car shut off while still driving. I tried starting it back up but it kept making clicking noises really fast like a machine gun. I had just bought a brand new battery about a month ago too.
I was able to get another brand new battery and installed it, it cranked normal and I was able to drive home but the whole time the battery light stayed on and solid, no other lights were on.

Fast forward to today, my car started up without any problems, I drive out of my driveway and then all of the dash lights came on. I was able to turn back into my driveway, I shut the car off then tried to start it back up but got the same machine gun noise.
While trying to start it the first couple times my dashboard lights lit up like normal and the beeping sound for the key in the ignition can be heard. I tried again a couple more times and noticed my dash lights weren't lit and there were no beeping noise, now the machine gun noises were gone as well.

I read somewhere I should try checking the battery with a multimeter. While connected, my battery was reading around 4-6 after trying to crank the car. I noticed the voltage would go back up to around 11 or so if I let it sit there for a minute.
Between letting it sit for a minute and trying to crank it every now and then I noticed my dash lights and beeping noise for the keys would turn on every other try. With the brand new battery I just bought disconnected from the car, checking the voltage and it was now reading around 5ish.

What I've tried so far: cleaned ground wire connections, cleaned battery terminal connections, changed out battery terminal connections for new ones, checked all battery wires for corrosion/frayed etc, used my old battery that had voltage around 12.40 or so (starting the car also drained this battery),
I jump started the car: the car actually started up, I went around and removed the jumper cables but then the car died, tried jump starting again but only got machine gun noise with no dash lights, let it sit for a few minutes with the jump cables on, tried a few more times and then got no noises and no lights after a while.

I haven't done/checked anything dealing with the starter or alternator, yet. Just trying to do the simplest stuff first. Hope someone can point me in the right direction!

In your first post you mentioned installing a new battery after the initial failure, driving home on it and having it fail to start the next day. The facts that the "battery light" remained on during the drive home, the failure to start the next morning and your low voltage readings, strongly suggests a problem with the charging system which could include the alternator, bad connections, bad voltage regulator, etc.

The plates of modern car batteries are structurally weakened by deep discharges and your new battery now has been aged by several of these, so try to get things fixed soon. This doesn't mean you need to replace the new battery tomorrow, but be aware of the potential for premature failure and if you're concerned about reliability consider replacing it before heading into a deep winter.

A good way to monitor your car's charging system is to get a digital voltmeter that plugs into the 12vt accessory (cigarette lighter) socket. Learn it's patterns and check things out if it deviates from normal. In your recent case, it most certainly would have shown low voltage when the battery light was flickering, and if a battery is getting old it might give advanced warning by showing deeper drops combined with longer recharge times after starting.

 

The bolt/post on alternator is the +
The test I asked for is Neg Battery Terminal to BODY of alternator..... it is resistance measurement of the GROUND wires for the charging of car. Need to set MultiMeter to resistance. Looking for a very low resistance or there is a ground issue... "then maybe removal" of alternator and cleaning of the mounting points can put things back in working order.

Please complete the resistance test requested.

Simple charger will never reach 14.4v charging a battery...... only your alternator charges at the 14.4v range.

Many autos will not run below 12V... thus your idiot lights came on.....
Clicks you heard were the soleniod/ fancy name for relay to energize the starter...... very very common cause/effect

Running lights, radio, other stuff mentioned, till you resolve issue charging & voltage was a mistake.... you will not get far driving at night or electrics on

 

I'm not sure what ohms to set my multimeter on so I set it to 200 ohms. I touched the negative probe to the negative terminal and positive probe to the alternator case, I got a reading of 1.1

 

Just about to leave the house.

That is toooo much resistance and one of the problems or the problem....
we need to get the resistance down to .1 or .05 range or so would expect

Please do the test again... and scratch the body of alternator with multimeter probe.... aluminum oxide on the outside of alternator is not a good conductor. Get down to cleaner metal and take resistance again. Also do the same test neg battery to engine block.... scratch for good contact there also.

I will be back in minute.... and will help you correct the high resistance

Have you done alternator work, replaced accessory belt, or anything like this?

 

Just about to leave the house.

That is toooo much resistance and one of the problems or the problem....
we need to get the resistance down to .1 or .05 range or so would expect

Please do the test again... and scratch the body of alternator with multimeter probe.... aluminum oxide on the outside of alternator is not a good conductor. Get down to cleaner metal and take resistance again. Also do the same test neg battery to engine block.... scratch for good contact there also.

I will be back in minute.... and will help you correct the high resistance

Have you done alternator work, replaced accessory belt, or anything like this?

Oh wow, ok. No I haven't done any alternator or belt work. I'll do the test again in a second and give update.

 

I could not get mine lower than yours in resistance. I scratched the body and have a aux ground wire to the body of the alternator.

Did you mate and unmate the electric connector to the alternator.... look for corrosion or issues.... cleans contacts with this action... it wipes the contacts and the oxide is not very conductive.

Ck the belt and see if loose.... that can also cause a low charge situation.... Also look at the bottom side of belt.... does it have cracks or look shiny. Have you been hearing any squeels from the engine area when 1st starting or running around?

After you get your battery charged up.
Will start the car and see what the engine running VOLTAGE is on the battery terminals.
We are looking for 14.4 v at idel or just a little more rpms. If just the battery voltage of 12.6 to 12.8 or what the battery resting charge is after a 4 hrs after off the charger. Record this resting voltage.

IF Failed, not putting out 14.4V running
Take your alternator out, and have it tested at auto supply store.... will bench test it.... it is free test

When alternator is removed....
note there is a copper button on one side of the pivot mount for alternator. Clean off the dirt, and wire brush it till it is clean copper. That is the main alternator ground..... I put copper antiseize on this to keep it from oxidizing. Clean off the other mount point with wire wheel, I clean up the bolt threads and the bottom side of bolt heads too. CAR is DC Current/Voltage..... means every electron leaves the battery, does work, then uses the ground path to go back to battery. The grounds are as important and the red wires. That is why I run a 10 awg ground wire to the mount of alternator and starter. TWO of biggest amp users. I also put copper antizeize on the bolt threads and under the bolt flanges to keep better ground and hold of oxidation.

If the alternator passes bench test... the clean up will make a better install
IF Need NEW ALTERNATOR will make for a better install with good grounds... or better grounds

This work will keep your battery, alternator, starter lasting longer and they do not work as hard. My 1994 Toyota is original alternator, battery from 2015 MN Winter, and second starter?? I think its been changed.

I think your alternator is going to fail a bench test.

 

I could not get mine lower than yours in resistance. I scratched the body and have a aux ground wire to the body of the alternator.

Did you mate and unmate the electric connector to the alternator.... look for corrosion or issues.... cleans contacts with this action... it wipes the contacts and the oxide is not very conductive.

Ck the belt and see if loose.... that can also cause a low charge situation.... Also look at the bottom side of belt.... does it have cracks or look shiny. Have you been hearing any squeels from the engine area when 1st starting or running around?

After you get your battery charged up.
Will start the car and see what the engine running VOLTAGE is on the battery terminals.
We are looking for 14.4 v at idel or just a little more rpms. If just the battery voltage of 12.6 to 12.8 or what the battery resting charge is after a 4 hrs after off the charger. Record this resting voltage.

IF Failed, not putting out 14.4V running
Take your alternator out, and have it tested at auto supply store.... will bench test it.... it is free test

When alternator is removed....
note there is a copper button on one side of the pivot mount for alternator. Clean off the dirt, and wire brush it till it is clean copper. That is the main alternator ground..... I put copper antiseize on this to keep it from oxidizing. Clean off the other mount point with wire wheel, I clean up the bolt threads and the bottom side of bolt heads too. CAR is DC Current/Voltage..... means every electron leaves the battery, does work, then uses the ground path to go back to battery. The grounds are as important and the red wires. That is why I run a 10 awg ground wire to the mount of alternator and starter. TWO of biggest amp users. I also put copper antizeize on the bolt threads and under the bolt flanges to keep better ground and hold of oxidation.

If the alternator passes bench test... the clean up will make a better install
IF Need NEW ALTERNATOR will make for a better install with good grounds... or better grounds

This work will keep your battery, alternator, starter lasting longer and they do not work as hard. My 1994 Toyota is original alternator, battery from 2015 MN Winter, and second starter?? I think its been changed.

I think your alternator is going to fail a bench test.

Thanks for the big help! I scratched the alternator case and it was still 1.1 ohms. I checked all electrical connections and they're clean. Belt is tight, no squealing or sounds while car is running.
When I had the battery charge over night and the battery was around 13.8v, I installed the battery and started the car. At idle the reading at the battery terminals were around 12.2 to 12.6.

I'll go ahead and keep the battery on the charger and start the process of removing the alternator to get it tested.
Will update soon, thank you!.

 

Some thoughts:
1. As other's have mentioned, absolutely do not disconnect the battery while the car is running. The charging system depends upon the battery being in the circuit in order to stabilize the voltage on the system and in particular to absorb energy from high voltage spikes the alternator generates that otherwise can damage electronics - I've seen modules destroyed this way. Having heavier loads like lights and fan motor on will help with spike absorption, and one might get away with it, but don't count on them alone to stabilize things the way a battery does. Electronic modules like the ECU also should have some degree of protection built in to them but it's not always sufficient.

2. Resistance readings aren't reliable if there is any voltage present across the part of the circuit you are measuring. Applying a voltage across ohmmeter contacts also might damage the meter. If unsure whether a voltage might be present, you can first connect the probes with your multimeter in the voltmeter mode, working down to the lowest voltage (most sensitive) range. Another way to confirm if a resistance measurement is valid is to measure the resistance, reverse the probes and repeat the measurement. The two resistance readings should be the same, but if they differ there's likely to be voltage present and the reading isn't trustworthy. It's best to disconnect the battery (removing the negative terminal's connector) before checking ground contact resistances such as those associated with your alternator, or you could first disconnect all other wiring to the alternator.

3. An auto parts store, or a mechanic, can perform initial charging system tests on the intact system. You later might need to remove the alternator for more comprehensive tests.

 

Update: I just said screw it and bought a new alternator. I didn't get my old one tested, there was a ton of rust on the alternator mount bolts kinda just told me how old it is, was super hard to pry out because of it. I'm glad it was super easy to remove.

Before installing my battery, it has been charging for a couple days, voltage was at 13.36v.
I installed the new alternator, battery light is gone.
I checked the voltage of the battery with the engine on and battery installed and it is reading 14.4v, perfect!

I left the car on with heater on, headlights on, radio on, doors open for about 15 minutes. Battery light stayed off, checked voltage of battery again and it stayed around 14.4v.

So, thank you all for all for the suggestions and help! At the end of it all it was a bad alternator.

 

Update: I just said screw it and bought a new alternator. I didn't get my old one tested, there was a ton of rust on the alternator mount bolts kinda just told me how old it is, was super hard to pry out because of it. I'm glad it was super easy to remove.

Before installing my battery, it has been charging for a couple days, voltage was at 13.36v.
I installed the new alternator, battery light is gone.
I checked the voltage of the battery with the engine on and battery installed and it is reading 14.4v, perfect!

I left the car on with heater on, headlights on, radio on, doors open for about 15 minutes. Battery light stayed off, checked voltage of battery again and it stayed around 14.4v.

So, thank you all for all for the suggestions and help! At the end of it all it was a bad alternator.

Just curious, what’s the brand of the alternator, where did you buy it and how much did you pay?

 

sounds great!!! and good to do the work yourself

you cleaned up the mounting point pivots, and the copper button, and the bolt threads & under the bolt head/flanges??

congrads

 

I cleaned the battery wire that connects to the alternator. I didn't think to clean the mounting bolts and flanges, not sure what you mean by copper button.

Just curious, what’s the brand of the alternator, where did you buy it and how much did you pay?

I just went to the autozone near me, I got a duralast it was like 330$ with a 25$ core return or something like that.

So far I've driven it for a couple hours running errands that needed to be done, still no battery light! I can positively say that it's fixed!

 

Glad you had a good outcome. Moving forward, have you considered getting one of the little digital voltmeters that rides in your 12vt. (cigarette lighter) socket? Their continuous display would enable you to monitor system voltage over time and enable catching future failures at their onset. They run ~$15-20, some include USB charging ports.

 

If the battery is only getting 12ish volts with car running, alternator has passed away