UA results from Voltage Spike..
 

When you go WOT the A/C compressor clutch circuit is opened. That might/would result in a HUGE voltage spike in all of the 12 volt circuits, along with a fairly high level of EMI & RFI (Electro-Magnetic Interference & Radio Frequency Interference) due to inductive kickback.

Might that cause a Disruption of the engine/transaxle ECU's firmware instruction execution sequence...?

The way I discovered my 12 volt battery in our 911/996 was not up to snuff was because I would get, randomly, various fault lights (mostly ABS/TC/"VSC"...) on the dash after beginning a drive, actually getting underway. The engine always started and only in retrospect did I realize it had been cranking slower than normal.

Does Toyota/etc use any sort of "snubber" network to snub out, eliminate, that voltage spike...??

Re: UA results from Voltage Spike..
 

Even the simple stuff I work on has an array of MOV's guarding the front end V-regs and downstream logic core.

Of course on wheelchair lifts, signal integrity means the difference between the device serving as a mobility lift, or a catapult.... the latter being severely frowned upon. Through the years we have learned that Ham radio operators, wireless sprinkler systems and even high-output two-way radios on board can create EMF that must be filtered, snubbed or clamped.

West, you could seriously be on to something here. The cheese holes would need to line up just perfectly, but with the level of complexity in new cars the opportunity is certainly there.

Re: UA results from Voltage Spike..
 

Back in ~'92 Lexus decided to use the rear window defrost grid to recieve the Key's RF lock/unlock signal. It didn't work well initially.

TSB called for adding a "choke"/inductor in the grid line going to the 12 volt power source so the RF signal wasn't mostly shunted off into the 12 volt system.

Re: UA results from Voltage Spike..
 

There is no A/C compressor clutch on the TCH. The compressor is directly driven via an electric motor...

Re: UA results from Voltage Spike..
 

The major failures seen to be the non-hybrid Toyota vehicles.

Re: UA results from Voltage Spike..
 

Question of the day:

Are people that overuse acronyms just pretentious or are they really completely clueless that most readers don't have a clues as to what they mean?

See what I mean?

Just sayin...

Re: UA results from Voltage Spike..
 

Wow! I mean... New York, but, upstate, not the city. Sorry dude. Couple of geeks, chatting away on a board built for car geeks. I didn't think it was possible to offend. Acronyms are sometimes used to save typing when discussing common terms. Should I included a full thesaurus index with every post I make, just in case anyone happens to stumble across it?

I'll check my pretentious tendencies and the thrill I get by wagging it about in front of strangers and I'll try to help. And by the way, non of the acronyms used are unusual when discussing modern automobiles. It ain't all chokes and clutches anymore:

WOT = Before 2001, this meant Wide Open Throttle
UA = Unintended Acceleration
RF = Radio Frequency
VREG= Voltage Regulator
MOV = Metal Oxide Varistor, device used to clamp voltage spikes
ECU = Electronic Control Unit

Again, no one came in here and said: "Hey, I know.... let's use some big words and see if we can annoy Mark Cohen from Upstate NY"

These are all very common items on modern cars. I hope this helps.

Re: UA results from Voltage Spike..
 

My goodness. Such sensitive souls. I hope you all found your fainting couches before you got the vapors.

But thank you for explaining the acronyms. I don't feel so stupid now.