I would hope even a first year tech would know the importance of ground potential and its effects on the systems tied to the ECU. I know I sure do. If not, people will be replacing a LOT of sensors and modules without fixing the many ground related issues that come up in shops. Like I stated above, it does not take much to start interfering with the readings when we are measuring on small scales. That is preached and stated in the manuals as well. And either right before or right after connecting an OTC (or similar diagnostic tool) to any system, I at least check the major grounds for higher than spec potentials. Those types of issues can play head games with you all day long if you are not prepared to look for them. And when you have the slight variations in ground potential coupled with the operational tolerances of each sensor (every electronic devices accuracy is a result of the tolerances of all internal components) over time, these issues can be hell if you dont look for them to start with. For example, a sensor is a couple of years old and its tolerance has shifted.... on top of that you have slightly bad ground. You replace the sensor, which seems to "fix" the issue... not to far down the road, as the ground deteriorates further.. the sensor will seem to fail again. It is these intermittent and slightly out of tolerance issues that chase us down the road. This is not saying that the kit above is making a huge difference, only stating the importance of grounding in the system.

 

Exactly.

 

While we're on this topic...anyone know if replacing the grounds/alt->battery wire in your scion will violate any warranty?

 

Hey engifineer, it's been 20 years since college, did I get it right

 

Wow guys I think I just blew a capacitor

ScionDad: I downloaded the full electrical manual last night with the missing pages and alas still no AC control diagram, so this weekend I'm diagramming it myself and will pass my findings onto you.

 

That would be sweet. I haven't given up yet

 

Together we can make a difference.


(OK I admit, that was ___, but I couldn't help myself)

 

Shoot, all the people that want blue...come up with a solution and sell the mod

 

As for the caps on a mainboard, are you sure they weren't bad caps?

I have seen them too and I don't beleive they ever had anything to do with a bad power source. I had three identical mainboards from three different clients in three different homes that were brought into our shop for "crashing" within a two week time period. They all had bad caps. The boards were manufactured at the same time(two years ago) with the same caps and they all failed. I see it all the time.

I'm not saying you are wrong, I'm saying that there are other possible reasons and solutions for these problems.

If these cars that are not much more than a year old are having sensors fail due to bad grounds, you need to get some warranty work done, not run wires all over the place while crossing your fingers.

 

I see what your geting at. Let me elaborate, this was on a 2 y.o. HP P.O.S. that had been running fine for most of that time. This problem started to occur over the course of a week when all of the sudden the system was shutting down and restarting without warning. I took another computer (same HP crap), and put it in it's place and low and behold, within a week it too exhibited the same issue. Under further examination (and lots of cursing), both computers shown the same thing on the boards, bloated caps. I whipped out my trusty multimeter and tested the power outlet, Nuetral-Ground was spiking from 1.2V to up to 4V! Now I have always been taught that N-G should not exceed a 1V and have seen results of such spikes on less sensitive equipment back when I repaired Micros workstations.

Now after reading the article you supplied, I'll accept that this may have been coincedental but that didn't excuse the high N-G voltage I was reading and that needed to be fixed regardless.

 

Ok, now that we have electrical kindergarden out of the way, exactly where in your soliliqy do you explain where the added performance is? Nice primer in electronics though. All you address is audio. Here's something I learned in school long ago: When working on problems as you state, sure everything has some resistance, but for our situation here let's assume chassis resistance to be NEGLIGABLE. Here's something I learn constantly in my job as a Toyota Master Diagnostic Technician: Chassis resistance, for all intents and purposes is NEGLIGABLE. By your THEORY, misguided in this application notwithstanding, why not use 0 gauge wire from the neg. terminal to every electrical component that you feel needs a better ground? More is better right? The funny thing is some of you guys read a lot more than you do! Yeah I went to college (twice!) and the one thing I learned when I started working in the real world was that I truly didn't know ____! I am just under the impression for some reason that when it comes to Toyotas and repairing Toyotas, I just might not be as dumb as you think. I also can assure you that Toyotas engineers are not as dumb as you think. Maybe you are simply overestimating your smartness?

 

And exactly what is it you guys are trying to do? I may be stupid when it comes to most things but I might have a solution to YOUR problem.

 

No one is saying you're stupid Scott. Not by a long shot. I've read some of your posts and you know what's going on.

We changed out he LED's in the center console with blue. Well, for some reason, everyone that did blue in the center console, the blue is dim. WHen I press the AC button, it lights up bright (the indicator), but the back lighting is dim. Any ideas would be sweet. We know the blue LED's need a min of 3.2 volts to operate full bright where red, white, green, amber, etc only need 2.2volts. In the gauge cluster, blue is bright and sweet. So, we have been trying to find schematics of the heater control board to reverse engineer it to see if there is something we can do. Maybe toyota has a fix? Any ideas?

 

What are you rambling about? Overstating my "smartness"? What is smartness?

Anyway, here is the basic concept. We are dealing the electronics. In dealiing with electronics, as you well know, they are not tolorant to dirty power. I was being somewhat facetious, but not completely in my "theory". Scott, this is silicon, so open the mind to a bigger pic. What controls the throttle on this car? What controls the A/F mixture? What controls the audio? What controls all the sensors all over this car.....down to the friggin tire pressure. Silicon sparky.

Why not run 2/0 cable while I'm at it. Scott, there are 3 basic approximations in dealing with this. However, the 3rd one is the most important I also understand if I can choose to have a "clean" power system or a dirty one, I choose clean and all the benefits that come with it. Esp for $20. I don't care what Toyota tells me. I can read a meter. I've explained enough.

As for me reading as opposed to doing. Um Scott, I'm a 40 year old EE major with a a minor in Electronics Engineering. I am a senior partner in an organization that builds cellular/PCS systems from raw land up. Been working engineering, audio and high power rf (100KW+) from vacume tube days to present. I'm not stating anything but what I understand to be fact as a seasoned "professional". I have no agenda and frankly could care less if you are anyone places some ground wire in your car. I offer my advise from my background. Don't like it, ignore it.

You on the other hand knows what Toyota tells you. If toyota can save millions doing it the way it is now, or spend millions to do it better, but you as the customer won't notice ANYTHING....what do you think they will choose?

My brother runs NHRA 3200whp funny cars and guess what.....he has one of the most elaberate ground systems you could imagine and I had little to do with it. Ever seen a "real" NASCAR. Look closely.

The theory is sound, the results are realized, end of silly discussion.
Thanks.

 

I couldn't have summed it up better myself! I think your 'smartness' is increasing. If the customer won't notice ANYTHING, why in the hell do it?!?!?!?!

 

Did you ever consider that you might have a substandard ground? Haha!!I couldn't help it!!!! Actually, what is the forward voltage rating of the LEDs you are using? There is no available schematic of this unit outside of the factory and you can't get it. Time for plan B. I don't recall if these lights dim when you turn on the headlights. If they do and you want the new ones to do the same it will add one more circuit. I would isolate these new LEDs on the board by scraping a break in the printed circuit on the positive side.(let's just assume just this once that the factory ground will suffice! ) Then hook up the LEDs with 30ga. Kanar wire so they can be powered remotely. How many LEDS , what is the forward voltage, how many Ma each, and I can figure the proper resistor for max brightness with good life. This would then be wired to an illumination wire (green) for the incandescant bulbs. The lighter light is ususlly a convienient place. If you want them to dim when the lights come on, another circuit and some diodes will be required. It would be easier to not have them dim. Then they can get the proper voltage and be very bright. Like me!

 

You seem to miss so many points in your above posts it is scary... how many times did I say that I was not advocating the elaborate grounding system, only stating the FACTS on grounding and its importance. You do what I have seen you do in other posts.. talk about how you are a Toyota tech and bash peoples knowledge... talking about how our schooling means nothing... so you want to know where my experience and knowledge came from? Well... my father has probably had his hands under more hoods than you have ever seen.... he is pretty much feared by all 6 dealerships around his shop, because MOST of his customers came to him because the dealerships could not properly troubleshoot and repair their electrical and mechanical issues. He has been going to classes and obtaining REAL WORLD experience since the first ECU was placed in a vehicle, and I have yet to see him take a problem he could not figure out. I was at his shop learning from him starting at 10 years old... could perform most basic mechanical fixes by the time I was 12,have helped him build 600 HP+ engines and worked on and off for him until I began college. I have NEVER once had anyones hands beneath the hood of my vehicle, including his... I was taught to learn by doing and ask questions when needed. I learned how to troubleshoot (using OTC diagnotstice tools) ODBII not long after it came out. I went to college and obtained my masters in engineering starting when I was 21. . So I doubt you are going to slam me much on my knowledge and experience. So dont try. And from the knowledge I have seen in ScionDads posts and messages I dont think you are going to teach him much either. How many times did I say that I was only stating the facts on the importance of grounding and not saying that the grounding kit makes a huge difference in this application? Or did you even thoroughly read the posts? And what do you consider NEGLIGIBLE??? On sensors whos entire typical range of measurements range somewhere around .5v or less... even a .05V change in ground potential is at minimum a 10% change... that is more than NEGLIGIBLE. I cant believe any "TOYOTA TECH" would not see this... like I said.. every manual on the planet preaches this. I can count 4 cases in the last 2 years that my father has corrected by simply tracing a simple poor ground and fixing it... to the pleasure of the customer who only paid for his minimal time to trace it (as he does not charge flat book time or charge for replaced parts that did not fix the issue). Two of those (maybe three if I remember correctly) spent a week or more at a dealership and were charged for mulitple sensor replacements by ASE "techs" that never fixed the issue. One flat out told the customer that he had replaced everything he knew and just gave up. No one was bashing your knowledge or was even really arguing with you. We were having a discussion about the effects of ground potential on a control system (which by the way , was one of my emphasis in college and about half of my experience since... so I am not talking out of my ___) . I love how people just assume that automotive electronics do not follow the simple rules of physics that EVERYTHING follows. So either from a textbook knowledge sense or a real world experience sense ... I feel pretty comfortable talking about it., and from what I have read, ScionDads knowledge is a very valuable resource here... he has many more years experience than I do and I am sure could teach us all a little. Stop thinking that because you went to classes and are a "tech" that you have nothing else to learn... because we all do. Have a little respect for people for a change.

 

For those discussing the console lighting... when the blue LEDs come in for my gauges (I ordered extra) I plan on doing the console as well. I am guessing that there is a higher than needed voltage source that is used to power those (which is normally the case), and a load resistor used to control the current through the LEDs. I am going to trace the circuit back to that resistor and recalculate the value to provide the proper voltage and current for the 3.2V LEDs. I will let you know of the results. All that should be needed (if my idea is correct) is a replacement surface mount resistor for each LED. As long as the overall voltage source is over 3.2V it will work just fine. The way to tell is to find the resistor inline with the LED and measure the voltage drop across it and the LED together. If it is more than 3.2V, then we are in luck. If not, I plan on finding the power supply and working to change it. I am **** in this sense, I would rather replace the proper components on the board than add extra hardware or wiring ... ScionDad, have you had time to check this yet?

 

If I was overly harsh in my above message , forgive me. But I have seen more than one post of yours , Scott, that sound too much like you are bashing everyones knowledge and pushing your own way above. If that is not your intent, I am sorry.. but that is the impression I get... and if you read many of my posts you will see that one thing I cannot tolerate is someones lack of respect for others.

 

jmiller is going to take a look at it this weekend as well. Keep us up to date please

Oh and I see you read some of scott's work as well.