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post #101 of 119 (permalink) Old April 2nd, 2013, 23:22
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Thanks Jason!
Here is the page from the 2001 Avalon (1MZ VVT-i) book about the P1705. Looks like it is pretty complex:


Apparently from reading the transmission operation description it looks like the ECU knows what gear the tranny is in because it tells it what gear to be in by controlling the solenoids. There are ECU input signals called "R", "L" and "2" so maybe those let the ECU know when the tranny is not placed in Drive. Those signals seem to be, when active they apply +12V to the ECU pin. So maybe I will try to apply +12V to the "R" input so the ECU thinks the tranny is in reverse, which in theory should remove a condition for the P1705 test. I think I tried that earlier but grounded out the "R" pin and it didn't work, but looking at the diagram now it needs +12V. On my wiring diagram the "R" pin is pin 8 of the middle plug set (middle one of the 5 ECU plugs).
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post #102 of 119 (permalink) Old April 3rd, 2013, 15:39
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Yeah I looked at that along with the Solara EWD, which is why I said the earlier ECUs are more limited than the VVT-i ones.

Reverse could be plausible since there's no reason for the ECU to monitor input/output shaft speeds as there's no other reverse gear to shift into. You'll have to try it out.

I'm not sure how the ECU will react when you're going 60-70mph in reverse (as the ECU sees it). There shouldn't be any timing cuts for shift points, but I wonder if it'll start acting strange.

Long-term test time, I'd think.
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post #103 of 119 (permalink) Old April 4th, 2013, 09:52
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OK, so I hooked up a +12V wire to the Reverse pin on the ECU (E6 middle plug, pin 8). I thought it was going to work but alas P1705 came back. I am wondering if those P1705 parameters are correct from the tech manual because sometimes I get the code even before 40MPH.
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post #104 of 119 (permalink) Old April 4th, 2013, 11:23
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dang i was hoping that would work
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post #105 of 119 (permalink) Old April 4th, 2013, 11:26
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Quote:
Originally Posted by Rdubs
OK, so I hooked up a +12V wire to the Reverse pin on the ECU (E6 middle plug, pin 8). I thought it was going to work but alas P1705 came back. I am wondering if those P1705 parameters are correct from the tech manual because sometimes I get the code even before 40MPH.
The ECU wants to see a waveform on NC+. It's like not having a crankshaft position sensor plugged in. The ECU needs to know the shaft+drum are turning basically.

The 2000-2004 Avalon ECU checks input shaft speed in ALL gears at any speed. The 1999-2003 Solara ECU only checks 3rd/4th and only over 20mph.
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post #106 of 119 (permalink) Old April 4th, 2013, 11:32
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nvm

Last edited by Oteck; April 4th, 2013 at 11:35.
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post #107 of 119 (permalink) Old April 4th, 2013, 11:40
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That's an easy $20 at radio shack
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post #108 of 119 (permalink) Old April 4th, 2013, 12:00
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This might work if you can get the frequencies right:

Texas Instruments goes in-depth for you.
http://www.ti.com/lit/wp/snoa839/snoa839.pdf

Input shaft speed should decrease as you increase speed (after 1st gear), since you're using gears that get closer to 1:1 and eventually go overdriven. 1st gear will naturally have the highest input shaft speeds, so the ECU might want to see a higher frequency at low MPH and vice versa. Inverse basically.
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post #109 of 119 (permalink) Old April 4th, 2013, 12:33
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Quote:
Originally Posted by MidnightBlueMR2
That's an easy $20 at radio shack
What is. My kingdom for someone who can actually design a full setup.
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post #110 of 119 (permalink) Old April 4th, 2013, 12:44
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Quote:
Originally Posted by Jason.MZW20
This might work if you can get the frequencies right:

Texas Instruments goes in-depth for you.
http://www.ti.com/lit/wp/snoa839/snoa839.pdf
Thanks Jason, I looked at that but did you notice the output - the sine wave output is always above zero. The NC2 input needs it to switch between equal positive and negative voltages, peaking around +/- 3V. That's why I have have a hard time trying to find a function generator or voltage controlled oscillator, because it has to say that it goes positive and negative.
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post #111 of 119 (permalink) Old April 4th, 2013, 14:31
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Quote:
Originally Posted by Rdubs
Thanks Jason, I looked at that but did you notice the output - the sine wave output is always above zero. The NC2 input needs it to switch between equal positive and negative voltages, peaking around +/- 3V. That's why I have have a hard time trying to find a function generator or voltage controlled oscillator, because it has to say that it goes positive and negative.
You have to calculate your own wave using the equations. That's just a sample.

The waveform from the Tundra looks like 4 volts peak to peak given 1V/DIV, if I'm reading it right. I don't see why you can't create something like that. I can't because I'm not an EE.
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post #112 of 119 (permalink) Old April 4th, 2013, 14:42
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Just building something that oscillates at a constant frequency is only somewhat highly difficult mainly because you have to make sure it goes positive/negative and not just all positive, and also be able to set the amplitude. The problem comes in on varying the output frequency, it would really need to vary and be proportional to engine RPM. While it might be possible to just input a steady frequency which exceeds the P1705 error code input range, then the ECU would be seeing highly varying engine RPM and vehicle speed with a constant NC2 rotational speed - and who knows at that point how it would react.
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post #113 of 119 (permalink) Old April 4th, 2013, 17:00
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Try inputting the crank position signal (NE+/NE-) to NC2+/NC2- with shielded wire. Frequency is about 2x as fast (and all sorts of wrong), but it doesn't have a condition for high input shaft speed. Not sure how it'll like the long low pulse from the 2 missing teeth (36-2). But, 34/2=17, which is close to the 16 tooth drum rotor when only half the data is provided to NC2+/NC2-.

It could prevent this code since this is basically for lockup clutch operation, unless it gets smart and monitors throttle position and such. I mean, in an A/T, when the clutch lockup engages, the input shaft spins with the engine via a mechanical linkage, so the input shaft speed should be higher. High input shaft speed would either make it think there's high engine load or the lockup clutch is operating.

I'm about out of ideas after that, unless you create an idler pulley that's similar in design to the rotor then drive it on the P/S belt side of the crank pulley. You'd then need the NC2 sensor mounted correctly to detect the speed of the protrusions.
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post #114 of 119 (permalink) Old April 4th, 2013, 17:12
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What if you just wired it in parrallel with the crank pickup? The computer would then think that the input shaft is spinning about twice as fast as the engine which it might categorize as a coasting condition. The computer might only care to look at torque converter slip data if the input shaft is spinning slower than the engine.

EDIT: Jason and I posted at the same time.
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post #115 of 119 (permalink) Old April 4th, 2013, 17:40
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another thing the computer is looking for is the "Shifting". Even if you get the waveforms correct. It may still come back on for not seeing the differences between input and output turbines when it commands the shift solenoids. I am NOT talking about shift solenoid codes.
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post #116 of 119 (permalink) Old April 4th, 2013, 17:45
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I checked though and could not find at least on the 1MZ VVTI any output shaft sensor. Which is odd because it is an input. Maybe it just uses the VSS.
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post #117 of 119 (permalink) Old April 4th, 2013, 17:49
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If it doesn't have an output. Then it probably does use the VSS.
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post #118 of 119 (permalink) Old April 4th, 2013, 20:04
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Soooo....

1. "Sine wave is always above zero volts..." IF you took the sensor wires off and hooked them to a 'scope, you'd see the signal shown BECAUSE one of your reference connections is actually the 'scope probe Ground. So, ANY purely inductive pickup like that will produce a sinewave output that goes above and below the reference connection.

In this case it's Ground, but if you were to take one wire and set it to +5VDC above engine (ECM) Ground (or Test setup ground), you'll have a signal swinging above and below +5. Because there are assumptions being made about this signal, I'll disagree with the necessary voltage swing (aka, Reference). It is quite possible that the ECM (internally) has a differential amp receiving those two wires and outputting a square wave, which will for sure be Ground referenced.

2. "The Tach signal is a square wave". Is it? From years ago (9?) I remember that it might be pulse waveform. If it HAD to be a square-wave, put it through a CD4013 "D" flip-flop to square it up, but that will divide by two. It could then be multiplied by some other number if necessary.

3. Arduino - sometimes I forget that we have a "real" programmer in the bunch, Mr. Embedded. He raises a very good point, especially from an experimental and developmental point of view - use a device that can be "easily" programmed for multipliers and also has the ability to provide logical decisions. For example, you can set thresholds for the measured frequency and output if necessary, based on those thresholds. These can also be used and are fairly easy to program: http://www.parallax.com/tabid/295/default.aspx

4. If you really need a signal that is not Ground referenced, it's likely that this could be created with a flip-flop output using Q and Q' as opposite polarity signals. Resistor dividers for each output could drop the voltages down to something appropriate.

5. Using the Tach signal might be a bad idea, as the ECM will think that the car has never stopped. Again, a microcontroller that can make decisions based on other logical conditions might be necessary.
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post #119 of 119 (permalink) Old May 25th, 2013, 23:50
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Quote:
Originally Posted by Rdubs
I checked though and could not find at least on the 1MZ VVTI any output shaft sensor. Which is odd because it is an input. Maybe it just uses the VSS.
I just read this thread through in anticipation of my own VVTi install.

From what I can see, the signal should be satisfied by using:

1) Crank signal or crank/2 for NC2+/-, and

2) VSS for VSS/output signal

This shouldn't confuse the ECM with regard to input speed/output speed and shifts, as the RPM will vary with actual manual shifts (real RPM/NS decrease as VSS increase) and the relationship should be similar to resulting A/T values expected by ECM.

Only concern is if there is enough logic for those speed changes to disagree with resistor'd values for solenoid control.

That is, the ECU sends a shift command, the speed signal does not change at the appropriate time, error is detected.
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