Shuts off while driving and dash acting erratic?

INFAREL

MEMBER
2002 LEXUS LS 430
4.3L
V8
2WD
AUTOMATIC
238,000 MILES

Hello, this problem is driving me nuts. I’ve replaced the alternator, the camshaft sensor, the crankshaft sensor, ignition switch but (not the cylinder), and the ECU which was programmed with a paper clip in the OBD. Nothing has changed and the problem still occurs.

Please help.

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5 Replies

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

Wow, that is an interesting one. I have to ask a question. You indicated the alternator was replaced. Was the alternator an OEM Denso alternator used? I remember a few years back that the alternator itself (2 new aftermarkets did the same thing). Once an OEM alternator was installed, everything went back to normal.

Do me a favor. When this is happening, I need you to check the alternator output at the battery. All you need is a basic multimeter or voltmeter.

Follow the directions in this link and let me know what you find.

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

These vehicles are very sensitive to voltage issues. Let me know what the voltage is with the engine running and with it off.

Talk care,

Joe

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Sunday, November 20th, 2022 AT 9:18 PM

INFAREL

MEMBER
3 POSTS

Joe,

Thank you so much for responding. I'll definitely get a multimeter and try this out. Good question about the alternator. I’m not sure what brand I bought but I can check it. I bought it from a place called O'Reilly's.
Another thing I noticed was when I unplug, then plug back in the 5 harness plugs that connect to the ECU, the car will start. Whatever this is, it’s dramatically draining the battery.

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Monday, November 21st, 2022 AT 5:22 AM

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

If you are disconnecting the ECU and it doesn't drain the battery, it sounds like that is the issue. Inspect the wiring harness to make sure nothing is damaged as far as the connector pins. Check for anything that may have overheated and is touching. Also, check for any bare wires or loose connections.

Let me know what you find.

Joe

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Monday, November 21st, 2022 AT 6:31 PM

INFAREL

MEMBER
3 POSTS

Joe,

Thank you so much for responding and I will do. I’ll let you know what I find after that. I’m not a mechanic. I usually learn a lot from YouTube, lol.

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Monday, November 21st, 2022 AT 7:47 PM

JACOBANDNICKOLAS