Shuts off while driving and dash acting erratic?

Tiny
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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Sunday, November 20th, 2022 AT 9:10 AM

5 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 107,591 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
Tiny
INFAREL
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  • 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
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 107,591 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
Tiny
INFAREL
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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
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 107,591 POSTS
Hi,

You are very welcome. Let me know what you find and what I can do to help.

Take care,

Joe
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Tuesday, November 22nd, 2022 AT 5:48 PM

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