Electrical issue_GX460_ non start

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08-30-19, 09:01 AM

#31

Acrad

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First one is to the right of infotainment screen and second one is in footwell area of driver.

Attached are some other tests you can perform on OBD port with vehicle off. Step #5.

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CAN_COMM_Testing.pdf (103.6 KB, 106 views)

08-30-19, 09:08 AM

#32

tflash09

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Awesome, thanks for all of the info. Greatly appreciated!

08-30-19, 10:54 AM

#33

Jacket

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Quote:

Originally Posted by tflash09

Well, I charged the battery outside of the car to 14.2 last night. tried it again today and it did not start. Post attempt, the battery measured at 12.5V. Though at 14.2, the accessories did not have power.

Every fuse/relay has been checked. Strangely, I was able to start the car using the "place the key fob to start button method last night" as I was pressing the button for 10 seconds or more and then releasing. This only worked once. With the vehicle started, I still did not have power to door locks, rear lights, radio, Nav, power seats, etc. I was unable to repeat this result once the car was turned off.

The battery voltage did not appear to rise up to quickly and did not get to 13 when running. The Alternator may be a factor. Perhaps the ECU is fried as well.

When placing the battery on a load test meter, it measured fine in "the green".

Just so I'm clear, you removed the battery from the GX for an extended period of time (i.e., overnight), charged it, and then reinstalled? To me, it sounds like maybe a security system fault of some sort. I've seen similar behavior before on a 200 series LC after a weekend of camping. Behavior was: no start with the remote fob in pocket, no start with the fob touching the button - just dead with no evidence of crank or anything. Jumped and charged the battery - still nothing. Long story short, we finally got it working by pulling the battery for > 30 min, and then replacing with a good/fresh battery from another truck. At that point it started right up. So it was the combination of a bad battery that created a system fault in the security system - both of which needed to be addressed.

Despite some of the confusing replies in this thread, a resting, charged battery should be in the 12.6-12.8V range - certainly enough power to start the GX. A battery under charge load will jump up to around 14V. But even if a battery shows as charged, it may have a bad cell(s) and not be fully functional. I'm not sure if that's your issue here, but it might be worth a try if you have another known, good battery that you could install after leaving the truck without a battery for at least > 30 min to reset the security system.

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ltsr (08-30-19)

09-01-19, 05:36 AM

#34

tflash09

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Thanks Matt,

I was concerned about the battery as well. It definitely had over 12.8 at times when attempting to start. It's in the hands of a Toyota shop now.

Would anyone send their ECU's off to get fixed/ rebuilt (if the problem) or is it best to buy new?

09-01-19, 08:08 AM

#35

coolsaber

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If your vehicle started, but nothing else worked, probably a short 2 ground somewhere in wiring as you let the indy deal with it. Depends on how the ECU plays a part in this issue. If its a capacitor leakage etc, best bet to ask the guys on the LS400/430 forum (they have been dealing with a bad design).

Dont know anywho else who does Lexus specific ECU repair.