The ground wire is not going to effect how the car shifts sorry this is not a 90's ford were the ground wires get over loaded and fry everything electronic.

I have had that ground wire broken since I did my header install 2 years ago and my car shifts fine.

 

I was able to purchase three heavy duty thick braided ground straps from Amazon, which cost me only 10 dollars in total. Installed one between the transmission and body, and extra one at the right side of the engine. Will be testing starting from tomorrow to see if this impacted anything.

 

Am all about sorting things out.

Does anyone know (exactly) why Toyota added a ground wire to the A650-E transmission?

Were Toyota engineers resolving something or a matter of production line workers run amok?

2001-2003 LS430 used Aisin A650-E 5-speed transmission, as did the 1998-2000 LS400, however LS400 did not use a transmission ground strap.

The 2004-2006 LS430 6-speed transmission is apparently more problematic...or at least the electronics repair shop whose name keeps coming up is able to trouble shoot it...but it remains unclear exactly WHAT component(s) replaced or software modifications.

Yamae?

Thanks

 

It's not the transmission but the ECU which over time develops broken solder joints.

 

Grounding is one of the first things to check while troubleshooting electronic/electrical issues.

If integrity of a ground point is compromised by corrosion and/or oxidation, or separated ground then electronic circuits are affected.

Cold solder joints on ECU have not come up on the LS400 side (mostly capacitors).

Perhaps the LS400's ECU location inside the vehicle vs LS43O's ECU under hood has anything to do with failing solder joints.

Whether or not the LS430 ECU is cooled by vents, it is still operating in an environment that is significantly higher than the cabin.

The temperature cycling, never mind the heat soak on shutdown, is considerable...and this expands and contracts the circuit board.

Returning to the unanswered question concerning the grounding strap...

Toyota made a conscious choice to add an extra "grounding strap" between transmission and chassis (vs engine only grounding of LS400)

Does anyone know what engineering input prompted Toyota to increase production costs by incorporating this additional component??

Thank you.

 

430 electronics are profoundly more sophisticated than a 400. As recently mentioned in another thread, the 430 has over 40 independent ECUs. I'd be surprised if the ground strap attached to the Trans is the only one that was added. Maybe Toyota Engineers finally recognized the high failure rate of the engine mounts and wanted some redundancy...? I'm also rather curious to see what Yamae has to say.

 

Can you clarify if it is the 2004-2006 LS430 six speed transmission or the 2001-2003 five speed transmission was experiencing shifting issues? Or both?

If both, does SIA work its magic on 1998-2000 LS400 ECU with same five speed transmission??

My read is the 2004-2006 LS430 with sealed 6-speed transmissions were most affected...

Thanks.

 

Check out full size chevy pickup and suv clusters, the ones that always have the stepper motor problems also suffer from solder joint failure on the large surface mount resistors. I wouldn't necessarily call it a cold joint, that would mean it wasn't done right from the factory this is more of a fatigue failure than improper soldering.

 

Trying to establish which of the 2 gear boxes experience “shifting issues” is certainly a lost errand.
Issues can arise from any of the following- incorrect fluid, incorrect fluid level, old fuel dampers, dirty throttle body, ECU glitches, etc...
Misdiagnosing any or all of the above under the “Transmission issue” umbrella makes it seem like a very common problem but in all actuality the Transmission is not the real issue.

Yes SIA Electronics will service a 400 ECU. Their website is not hard to find- https://siaelec.com/product-category...repair-return/

 

First, do not wish to advertise a company that cannot provide a straight answer as to WHAT they actually repair/ replace/ program on 2004-2006 LS430 ECU...

When we take our stereo for repair, the shop advises the faulty component and labor costs before obtaining approval from customer to effect repairs....

On that topic, I contacted said vendor as to actual service performed and was given a B.S. answer....and based on that interchange DO NOT recommend them.

The reason I am parsing out the 2001-2003 from 2004-2006 transmissions here is because the former is less problematic than the latter and redirect attention to the grounding strap question

So we have an A650-E transmission used on 1998-2000 LS400, 2001-2003 LS430.

Can't seem to acquire an answer from.anyone to the question why Toyota added the transmission ground strap.

 

Was the ground strap added when the 430 was introduced in 2001 or with the A761 in 2004?
Seems like that info could make most of the argument a mute point.

 

Started in 2001

 

They are not saying how to fix it because they are the only game in town when it comes to repairing them. Tuners do the exact same thing, they spend tons of time and money figuring stuff out and dont want to share. Why should everyone benefit from the knowledge they have spent years accruing.

This thread can be debunked easily go put a voltage stabilizer on your car and then tell me if it improves anything performance wise the answer is no. One little ground strap is not going to make or brake how the transmission shifts it is ludicrous to think a strand of copper could effect that.

 

Does anyone have information why Toyota added a transmission ground strap??

Thank you.

 

The new ECUs inside the car needed a better (shorter) path to ground to ensure reliability and they very likely added this path to ensure they are kept happy. It also helps to make sure no electric potential difference can build up anywhere in the car and is why you see new cars have ground straps to the exhaust etc

At least that what I have found working on the newest German stuff