+1
I agree with what MidCow3 stated.

Also, the negative connection isn't right to use that bolt. Please check the owner's manual. I recall reading that it should connect to hook like piece on the engine to be safe. It can mess up the electronics or ECU on this vehicle or it will be very expensive repair if done wrong. Just a heads up.

 

websurfer,
Unfortunately, some hard headed people who advocate that a ground is just a ground are in error... you can look up past threads on this topic.
Follow the owners manual, not what some poster's post says.... and you are correct, bolts or areas very close to the ECU can fry it..... just the facts.....
Ultimately, you will pay for a fried ECU, not those giving out mis-information......

 

The 1 time I used my NOCO for a boost, I connected the black terminal to a stud/nut lower on the fender. There are 2 ground cable connections down there and one was just close enough that the black lead reached, as the cables aren't long enough to reach to the engine block. I had no issues, but again it was only once.

Note that I may have figured out why my battery kept dying when I washed my car. I used to keep the fob in my pocket while washing. The locks kept cycling as I came close to the handles. I no longer do that, keeping the fob on a shelf in the garage. I believe the car stops communicating with the fob once the fob hasn't moved for about 30 seconds. I get a message on my phone/watch from the car warning me the doors are unlocked, similar to when I park in my garage when returning from a drive. I assume that's when the communication between the car and fob has stopped. The locks no longer cycle as I wash. Since I've done this, I've had no issues. So I'm guessing while the fob communicates, systems in the car are in a mode that drains the battery. Takes me an hour or so to wash the car, so maybe that is sufficient to drain the battery low enough to prevent starting.

 

Agree 100% with JasDmw. Just think of your keyfob or card fob as a cell phone that communicates whenever it can to your car. As long as it can reach your car it begins to communicate to it and will constantly, if your fobs remain close enough to it. When I wash the car or will have the doors unlocked for any length of time I prepare the car for what I'm going to do then I put my fob into a faraday pouch and leave it in the garage. The car will send my a warning on the app that the doors are open and unlocked but that's it. In fact when my subscription for the app ends in November 2025 it won't even do that anymore because I will not pay $20 odd dollars a month to be too lazy and actually go look at my car and make sure it's safe before I leave it for the night. Kinda like everyone did just a few short years ago before we all got a little too lazy.

 

One more time folks, i will explain for @websurfer , lab assistants, accountants, executives, lawyers, non-engineers and other forum members wat I said before is correct. "ground is ground" because metal conducts electricity, so any bolt connected directly to the engine of engine frame can act as a ground. If a metal bolt is not connected to the engine or engine frame the it is insulated from the engine or engine frame an basically has infinite impedance from ground and is not a ground. There is a rumor that the ECU will cause problems, because the ECU is not connected to the engine frame or engine. I think there was a rumor on the RAV4 forum that connecting ground to the ECU bolt cause the ECU to short out. This absolutely cannot happen on a normal ECU unless the ECU is somehow short to ground and then the ECU failure would not be caused by connecting to the ECU but rather because the ECU is not properly insulated. Again ,connecting close to a frame bolt near the ECU will not cause problems.

Thank you, @TheCDN your photo shows a perfectly acceptable ground bolt connection

Okay, the Lexus NX manual is pretty confusing and sparse about jump starting and could easily be confused by someone. Here is about the only item from the Lexus manual about connecting the


Ground (version Japan 2022 NX 350 h version 2022):

read (D) for connecting negative : Solid, stationary, unpainted metallic point away from exclusive Jump starting terminal ( so you won't accidentally touch Positive and Negative and cause sparks and short ) and any moving parts as shown in the illustration




Please let's not spread grounding rumors and old wives tales about grounding and my statements without proof. Thanks! Remember, I am trying to help

YMMV,
MidCow3

 

Look at this YT

 

Interesting video, but remember that metal conducts electricity and basically all of the 7 points the video says not to connect too are connected directly to the engine frame and are basically the same as the left connection point shown in the Lexus manual. The example shown in the Lexus manual is connecting to a metallic point and farther away is more convenient to show in a diagram and less prone to error for a newbie jumper. So it questions somewhat the validity of the video. But proceed at your own caution.

Signing off from this discussion. Good Luck folks and remember "a trickle charge a day prevents a dead 12 volter"

Peace and keep the 12 volts alive and healthy.



YMMV,
MidCow3

 

I think one of the reasons people should stay away from using the ECU (aka engine computer) as a ground is that its not really configured like a conventional computer. With a conventional computer the power supply handles supplying low voltage power into the computer boards and while it is possible to blow a mainboard with any malfunction, a vast majority of the cases if something goes wrong with power the power supply will blow but a simple replacement will find the computer itself is just fine. I've replaced many a power supply over my decades in IT and the computer itself is usually fine.

However an ECU doesn't work this way. It is directly connected to sometimes dozens of sensors and other modules and is actively measuring and switching both positive and ground signals internally for the various devices its communicates/controls. The potential exists for electricity to flow not only thru the frame of the car and around the ECU mounts to positive, but potentially with high current draws when boosting, thru the ECU itself. In normal situations I'm sure ordinary current will happily flow around the case and mounting brackets, but high amp surges have a tendency to seek out other paths. Don't let it be your ECU.

 

So, bottom line, egos aside , and those needing to be right all the time, (including computer assistants)... there is an area on the NX350h where you WILL short out the ECU if you attempt to jump your vehicle in the engine compartment. The video above (which has been posted previously posted on Clublexus) is solid information to follow and the most recent post from Droid 13 is spot on. Do your homework .

 

I'm thinking that maybe WILL changed to "Could" would be more accurate .?.? But I'm not willing to test this theory

 

There is a follow up video that shows clearly from Lexus where to jump start

 

Well, some think frying the ECU is a "Rumor". Perhaps those that think its a rumor should "test this theory"


LSFT, perfect video update...which tells us where NOT to connect the Negative terminal.... no more guessing, no more "groundless claims"..... : )

 

It would seem the rumors are ungrounded.

 

While we at ClubLexus know better than to ground it incorrectly. I have to think that some in the general public have had AAA or someone with less experience jump it incorrectly. After all, we know how frequently the 12v fails on this model.

I hear all the time of batteries getting replaced but no ECUs.

 

You know gamma&42's point just brought to my attention something that is typically quite common place in the engine bay of cars. And Lexus could simply spend a little now instead of 'us' spending a lot later. How about a few $0.05 labels showing where not to 'jump' from, that dealers could affix.

I mean I've had the dealer replace my fuel door hinge 3 times now to try and improve it's panel alignment (unsuccessfully) and while there isn't actually a part number for it, they always mention to me 'oh and the manufacturer sends us out new fuel grade stickers to put on the inner surface of the door, we'll put one on at next visit'. Well the last one was wrong it said 'premium only', the others said 'premium recommended' which is correct for the hybrid.

Why couldn't Lexus just say 'Hey this is something new we never thought of before but since a lot of people don't know how to jump start our hybrid's AND it's very likely that we're partly - I mean - mostly to blame with poor 12 volt recharging strategy, we'll label areas where you should not use as ground'. An ounce of prevention is worth a pound (or a lot of dollars) of cure.

They could read something novel like DO NOT USE AS A GROUND