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My ultimate solution might be to just hardwire an under-dash oil pressure gauge. I'm not getting into wiring harnesss issues with a nearly 20 year old truck.
"36" is the pin ID for the interlock out, which goes to the HV battery pack, through the service disconnect and then grounds at the right "C" pillar.
If the circuit failed open after the invertor, then the voltage at pin 36 would rise to battery voltage (12-14v). Since it stayed low, that confirmed that half of the circuit was operating correctly because it stayed at ground.
What would be next? What should the circuit voltage be at pin 35 when it is operating correctly?
If the voltage at that point went high, that would indicate what?
If it went low that would indicate?
The next move(s) would be?
BTW. This is the advantage of using a multiple trace oscilloscope, being able to monitor four channels at a time saves tons of diagnostic time. (I can actually monitor 14 simultaneously with various tools combined.)
If the voltage is too high that is a result of resistance and can be caused by corrosion/heat/a wire burning through on the power controller side.
If the voltage is too low, a problem with the supply side. Test the batteries? If they test good then the inverter is toast.
Sure, I can do that.
When the circuit is operating there would be current flowing through the circuit to ground and that current flow would be controlled by the circuit's total resistance. As the current flows through each resistor the voltage level will drop. The trouble tree shows the open circuit voltage at pin 35 to be 12v. But what is the voltage supposed to be when it is connected and operational? How much current should be flowing in the circuit?
In every diagnostic there is often information that makes analyzing the system easier and the answers to those last two questions are what you need to know. Try to find that information.
The voltage drop across each inverter resistor during normal operation is (I)(1) = I volts.
The operational voltage at pin35 = 12 - (I)(Rps).
Having that information in hand makes any diagnostic with that circuit much simpler, and in this case I had no choice but to measure and figure out the value of that resistor as it was presented. Without a spec however, how is one to know if there isn't some issue present that would be sufficient to have an impact on the circuit's performance but short of causing it to code?
As described, when the failure occurred Invertor pin 36 was at 0v, the thing is pin 36 should be at 0v (or at least very close to it) because that is the ground side of the interlock circuit. If someone disconnected the service interlock, pin 36 would rise to the source 12v signal. The question that needed to be asked and then answered by measurement is what was the voltage at Invertor pin 35 when the circuit failed and it was a 12v.
What does that mean, and what is the next step?
Got an electronics store near you? (aka a Radio Shack)
Get a 50 ohm potentiometer (pot) Use your ohm meter to measure it and set it to 40ohms. Now take a piece of electrical tape and do a wrap around the pot and across the adjustment knob to hold it in place. Connect one of the pins of the pot to ground and the other one to the oil sender wire. Attach your voltmeter to the sensor wire as well and position the meter so that you can read the voltage. Now drive the car and monitor the gage and the voltmeter at the same time and tell us what you see.
BTW this is where the oscilloscope outshines the volt meter, the oscilloscope will show even the slightest circuit error while the voltmeter can often miss the fine details. If you have a Hi-res function on the voltmeter or a bar graph display then that will speed up the display and provide more detail. (The graph function can update at as much as 40 times a second while the voltage display usually only updates about 4 times a second.)
My work troubles are on my mind (software troubleshooting) and I can't seem to purge them to get in circuit analysis mode.
Here is the math.
One open in a series circuit causes current to fall to 0 amps. The "normal" current in this circuit is found by knowing the correct voltage at pin 35 when the circuit is operating normally that value is 1.5v. However service information actually shows 0-1.5v if you look long enough to find it and 0-1v is too low.
The schematic shows two, one ohm resistors inside of the invertor assembly, so knowing the voltage drop across them we can solve for current. 1.5/2 = .75 amps. Since the current is the same at every point in a series circuit we can now solve for the internal resistor in the power management controller. Since the source voltage is 12.5, and there is 1.5 dropped after the invertor then the formula is 11v/.75a = 14.6 ohm and that is the value of the resistor. Steve keeps trying to say that some computer program should do that for you.....
Back to the Prius. Trying to wiggle the harness and connector does not have any impact on the circuit, does that mean the invertor does need to be replaced? ($4000) If not, what else should be done?
The idea that a programmer is going to write a routine to troubleshoot their other code is quite comical.
Regarding the circuit, UNCLE!
I ain't afraid of no ghost...
By using a fixed resistance, you take the possibility of a bad sending unit out of the testing of the circuit. Current does the work of moving the needle gage (not voltage) and the fixed resistance should result in the gage reading not changing, unless of course there is unwanted resistance somewhere else in the circuit affecting the current flow.
or...
http://phx.corporate-ir.net/phoenix.zhtml?c=85803&p=irol-newsArticle&ID=2233802
SELL BABY SELL!
An hours 'labor is an hour's labor. Yes, it takes a mechanic 13 hours to replace the clutch in my Mini Cooper, and if it takes him 13 hours to track down some crazy computer problem in 2025, on a 2017 Prius, then it's the same issue---do you put $3000 in a $4000 car?
Here is where it gets dicey, If you KNEW you could drive it another 50,000 miles trouble free it might not be a hard decision. You know your car and how you have taken care of it. It **should** be Ok after the expensive repairs are done.
Next week someone runs a red light and totals your 4000.00 car. Does anyone think for a minute that the Ins. company gives a rat's rear about the money you just spent?
Some tough decisions.
There is no guarantee that you won't need another $3000 in repairs, next month.
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A car with 150K is like a 70 year old man in very good shape playing tennis everyday. Could he play until he is 85? Maybe, yes. Could he drop dead of a stroke in 5 minutes? Sure, why not?
The problem with repairing 2017 cars in the future is that you aren't getting a new clutch for all that money, or a dent repaired, or recovered seats--you will have the electronics repaired, but the car won't look any different, feel any different--and your stack of "old parts" could probably be picked up by two fingers. It's going to be a very unsatisfying expenditure.
Let's face it---2017 cars are going to be disposable. You can only hope that your collision avoidance radar, your vibrating, cooled seats, your remote entry motion-sensing tailgate, your lane avoidance sensors, your bluetooth/wifi/nav and all the rest just keeps working for those number of miles you expect your car to last.
The scary part is how *integrated* everything is.
As doc memorably pointed out, when you say things like "stability control", that doesn't actually exist as a thing you can point to in your car. It's an entire nervous system. It's almost, I dare say, one of your car's "emotions".
"Drove away from the house without key fob in car. Got to destination and realized I did not have fob with me and could not lock the doors. Got back in car and restarted it 3 separate times with key fob being more than 8 miles away!"
2016 350is F sport
2,000 miles
Don't be surprised when cars in the future don't need any key at all and operate via learned facial recognition.....
Face recognition, eh? Might not be a good idea for a prizefighter.
Step: 2: Tell Your Tech the Symptoms (without guessing the causes)
What happened with that writer is exactly why I keep instructing technicians to gather all of the pertinent information about a vehicle issue, but when you start actually diagnosing the failure forget all of that and concentrate on exactly what the car is doing right now. This even applies to a problem that shows up when they are working on a given car. Traditional advice was to go back and look over what you just did to see where the problem (mistake) is and that is actually bad advice because it starts off with an assumption that isn't based on any other information. Of course it's logical that a new problem could have been an unintended result of the present service but starting off with a guess at any point isn't logical at all. What the tech has to do is close his/her eye's and immediately forget everything they know about the car and just analyze the new problem like it's a car that just came in the door with that condition. The result of that approach is they will go straight at the problem whether they caused it or not.
The parallel here was the tendency for people to go online and get guesses about what might be wrong with their car and then take those guesses and start shopping prices before anyone ever began to genuinely investigate the situation and prove what was really wrong. That activity caused more problems between consumers and shops than it ever solved. The only thing about that which has never really been investigated was if creating disconnects between the consumers and the shops was actually the intention all along.
Y is one typical cause of the X problem, but this time, the cause is Rare Issue Z. Since I am the expert, I make sure to identify the root cause myself. But I have seen IT analysts go in circles. For some who have a tyrannical boss who always feels the need to control the situation and point them them in a certain direction, the stage is set for a lot of wasted time and energy as the lowly worker does as they are told.
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Had a customer in the bay once when I worked for someone
else telling me " all you gotta do is..." . In front of the
boss, told customer "what you need is a 20 dollar bill, a
lawnchair and a twelve pack. The twenty rents my tools
,while I sit and drink the beer and watch."
http://www.autonews.com/article/20170104/VIDEO/301049816/first-shift-body-shops-battle-worker-shortage
A good friend of mine is a principal employee at this company, and has worked on this project for the better part of fifteen years. The result is rather impressive, and is the result of a Navy bid request that was, by all standards, ridiculously impractical (even today, but definitely back in circa 2002).
What's so special about it? Well, every component of the vehicle is modular, meaning that maintenance is a matter of swapping parts. Space and weight are at a premium on a ship, so there's no room for redundancy and no tolerance for down time.
http://www.acea.be/uploads/news_documents/ACEA_European_oil_sequences_2016.pdf
So far so good...
Mine: 1995 318ti Club Sport-2020 C43-1996 Speed Triple Challenge Cup Replica
Wife's: 2021 Sahara 4xe
Son's: 2018 330i xDrive
The biggest thing that consumers have to be aware of is how the oil doesn't just protect the engine, it also has to protect the emissions control system meaning the O2 sensors and catalysts. Ruin the catalyst by phosphorus poisoning on a newer BMW and the owner is looking at a repair that can easily go over $6,000.
Are Euro flat tappet engines similar to old American technology? Because the engineer at the 540 Rat blog has thoroughly proven that it is a good oil formula that protects an engine, that thicker oil does not increase protection, and actually reduces it. On his 800 HP rat motor he usese nothing thicker than 30 weight. He has shown that thicker oil slows the flow, and that reduced flow causes wear. Consumers should not put up with a $6,000 catalyst system. This is where gaining that last 2% effect exponentially increases cost. I love the environment, but never that much.
Now those are both 5W30's but 5W30 is a very large category and if you don't choose a product by the O.E. spec approvals or ACEA ratings you could mistakenly substitute a 10W40 for a 5W20 or vice-versa. He is correct in some cases and maybe not totally correct in others. A thicker oil will protect a flat tappet camshaft better than a thinner one. In fact when building an engine the oil selected should primarily be focused on exactly that, the camshaft. Then you should design and build the rest of the engine to match the oil choice that best protects the camshaft.
When hot-rodders first start playing they often start shoving in a different camshaft and valve train without any changes to the crank and bearings. They go to a thicker oil because of the tribal knowledge that thicker oil, and higher pressure is supposed to be better only to find out they end up starving some rod bearings and blowing the engine. While thicker oil is harder to wipe away it doesn't flow as fast as a thinner oil which means under severe loading oil that gets squeezed out risks not being replaced with fresh oil flowing back into the bearing. Thinner oil of course can be squeezed out easier, but since it flows faster it is replaced easier.
BTW it is a myth that oil under pressure floats the crankshaft inside the bearing, the effect of hydrodynamic lubrication is closer to a tire hydroplaning. Last I checked BMW wasn't marketing for a consumer to drive their cars.
Mine: 1995 318ti Club Sport-2020 C43-1996 Speed Triple Challenge Cup Replica
Wife's: 2021 Sahara 4xe
Son's: 2018 330i xDrive
"SAE" versus "real world." The rated SAE viscosity is measured at 212°F. Previously accepted engine operating temperature was 230°F, and who knows how far the engines exceed this, particularly BMW who eschews all other standards (because it knows better than everyone. ) The oil viscosity changes dramatically with the temperature change, so the viscosity in a hotter engine would be a complete unknown, and probably too thick. So here is a rating on the bottle that should be thoroughly adjusted for modern engines.
Instead, we'll leave that murky standard, and let all of the OEMs set their own temperature range, and sell you a bottle that you must use for $9 a bottle. Just great, another profit center for something we have all considered a commodity for a long time.
Everything you post does support your premise that things are getting far too complex and proprietary!