Tsmith1982

Hey guys. Past couple days my car has acted strange.

Driving last night the check engine starts to flash. Car running smooth. I pull over and restart the car and all is fine.

This morning while driving on expressway the slip light flashed 3-4 times and quit. This was on dry surface they car was definitely not losing traction.

Also it'll randomly flash message low key fob which it may be low but it only says it randomly like maybe 1X a month.

I know this car is an electronic beast. Do you think my car battery is not supplying enough volts and causing these weird issues?

qtrung909

I just had to replace my starter. Car wouldn't start one day, it would just click but i would get power to everything else. Then my vsc, pcs, and check engine light came on. The lights went away but it became hard to start the car maybe 4-5 tries. Replaced starter and haven't had a problem since but its only been a day or two since i got the car back. I did notice when i went through the service records that the former owner of the vehicle brought it into the dealership multiple times for not starting and their solution was to replace the battery.

halfcut

Once the car is running the battery doesn't supply any power, it is your alternator. A bad ground/connection could be the issue, or perhaps the alternator itself. Also could be the ECU.

Devh

That's not entirely correct with modern cars. Although the alternator does take most of the load the car also needs the reserve power of the battery in the circuit to stiffen the voltage quickly when demands exceed alternator supply. If you have a failing battery it can manifest it's self into electrical issues like this especially with Toyotas.

In this case both the battery and the alternator needs to be load tested before all other possibilities can be entertained.

swfla

iTrader: (1)

Agree with Devh. Also clean and tighten the battery post connections. From reading on the CL forum, there may be a problem with Lexus batteries. So, it could be the battery. If so, get a different brand than Lexus.
Alternators can go bad, if yours is bad, many recommend a Denso (Lexus) brand rebuilt or new rather than other brands due to quality of construction.
Good luck and let us know what the outcome is.

halfcut

I have run my 2013 Tundra for 45 minutes at night in the winter without a battery. Testing both is easy as well as checking for a loose connection while your at it. 20 minutes with a multimeter.

roadfrog

DevH has given you the best advice. Load testing the battery and testing the alternator will likely give you the answer.

enoch861

Check for any stored codes.
A flashing engine light typically means your engine is misfiring, so I'd check for any pending codes to see if the misfire code is in there.
Do change your keyfob battery too just to be on the safe side. Mine would sporadically warn me about it and then one day my key didn't work. Then it would start sporadically working and then stop. Replaced the keyfob battery and that problem stopped.
For the other symptoms you're having, have a battery place (like batteries plus if you live by one) check your battery for you. It's free too, so nothing to lose.

Devh

I'm sure will run fine at Idle and even driving for a short distance but it will damage the sensors and any of the sensitive electronics eventually. The problem with the battery being in the circuit is if it's malfunctioning it will have have an effect on the electronics. It might even take out the alternator.
In the past you could get away with running a car without a battery but once they introduced the complexity of electronics it requires a battery at all times.

halfcut

I thought it was a parallel circuit, I guess there is more to it than that.

enoch861 makes a very good point about checking the codes. there could be more than one thing going on.

Devh

I guess you could say it is a parallel circuit however the battery behaves like a big inline capacitor and without it or if it's malfunctioning it will cause voltage fluctuations and spikes.

R Z

Take the car to an AutoZone. They can test your battery and see if there's an issue. Should the battery test out ok, they also may be able to help you check the alternator as well. If you're in Memphis and need a good Lexus shop let me know.

Tsmith1982

What lexus shop do you use RZ?

R Z

I've yet to need one, but a good friend recommended Harris Quon Auto Service on Elmore Rd.
https://encrypted.google.com/search?...64bb4a4568b2,1

My son has a 99 ES and Lexus wanted to charge him a boatload of cash for a strut. Turns out Harris diagnosed the problem different, fixed it for about a third and the car runs great. I don't recall the exact diagnosis.

In any event, Harris was a Toyota master mechanic. His number is 901.385.7866. Address is 5290 Elmore Rd. I'd still head to AutoZone first.