Car stalls when headlight turns on/while driving/taking a turn

2002 TOYOTA AVALON

160,000 MILES • 3.0L • V6 • 2WD • AUTOMATIC

DULUXE2000

MEMBER
14 POSTS

Hi, over last few months my car has the following symptoms:
1. Car starts then shuts off when the headlight turns on.
2. Car is driving slowly (with headlight turns on) then shuts off when high beam turns on
3. Car is driving with speed (40km/h), suddenly shuts off then back up immediately.
4. Car suddenly shuts off when turn (at low speed).

I use a multimeter to check battery terminals. In one instance, the voltage reads 12.8 while car is running. I turn off and turn on the car it reads back to 14V range.

The issue is intermittent. I suspect it's the alternator but it's quite expensive to replace so I want to make sure it's the problem.

Appreciate your help.

Oct 2, 2020 at 9:40 AM

KASEKENNY

✓Experienced Mechanic
18,907 POSTS

I think you are correct. However, even though this issue is intermittent, let's just stop by a parts store that offers alternator test and have it tested. It may fail the test that will confirm this.

https://www.2carpros.com/articles/how-to-check-a-car-alternator

If it doesn't then clearly we will need to test it when it is acting up. However, it sounds like the this is clearly a battery strength issue so it is either a battery or alternator, if not both at this point. So it is worth while to have them both tested and go from there.

https://www.2carpros.com/articles/car-battery-load-test

When the load on the electrical system is too great, things start shutting off so the fact that the engine stalls when the headlights are turned on just shows that it is too much load for everything to keep running and the engine just stalls due to the PCM having too low of voltage.

Oct 4, 2020 at 9:14 AM

DULUXE2000

MEMBER
14 POSTS

Hi KASEKENNY1,

I did all the tests you mentioned (before and a few time mores after your reply) but they do not show clearly that either the battery or alternator are bad.

It turns out that (on a lucky event) the coolant is leaking from the radiator and spray into engine section. It might cause short circuit or something. I replaced the radiator on Sat and has been driving fine since. I hope it's the cause.

Appreciate your time and thanks for your answer.

Oct 17, 2020 at 8:50 PM

KASEKENNY

✓Experienced Mechanic
18,907 POSTS

That is always the best thing. Fix one obvious issue and it corrects the other things as well. That is great. Thanks for the update. Thanks for using 2CarPros.

Oct 19, 2020 at 8:54 AM

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