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Subaru E-Throttle TPS Wiring


Fodder

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I'm posting here because I don't seem to have privileges yet for the main forum. I have recently purchased an i88 and intend to use the E-Throttle feature with a 2006 Subaru legacy throttle body. Out of the 6 pins, I have determined the motor + and - terminals, but I'm struggling a bit to come to terms with the remaining 4 pins. I've tested plenty of standard TPS's so I thought I knew what to expect, with the exception of there being two TPS 'channels'. But, no matter which way I Ohm the pins I get static, unchanging Ohm values.

My question is, is there a proper method of testing the TPS's to determine the proper wiring?

Thanks,

Ron

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Hi Ron,

I am not familiar with you DBW TPS, however the following normally remain true for most DBW TPS's.

You have a 6 pin connector,

THROTTLE MOTOR +VE

THROTTLE MOTOR -VE.

5 volt REF.

Sensor Ground.

TPS Main.

TPS Sub.

Using a multimeter set to ohms, go across sensor ground and one of the tps input pins

The TPS MAIN OHMS should start high and go low as the TPS is opened, therefore the TPS voltage will go up as throttle is opened.

The TPS SUB OHMS is reversed to the main it will start low and go high as the throttle is opened.

So for example TPS MAIN might be 0.50 volts with the throttle closed and the TPS SUB might be 4.25 volts with the throttle closed.

Also take note that some DBW TPS's the TPS sub value may plateau at around 75 % , resistance wont increase/ decrease past this point.

Hope this is of some help.

Regards

Dave.

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Thanks Dave,

Pin 1 is Motor +VE and Pin 2 is Motor -VE. I've bumped those pins with 12v and the throttle plate opens.

The Ohm testing went as follows.

P3 & P4 = 3000

P3 & P5 = 3000

P3 & P6 = 3000

P4 & P5 = 173

P4 & P6 = 343

P5 & P6 = 173

My assumption is that P5 is 5v REF, P3 is sensor ground, P6 is Main, and P4 is Sub. The ohm readings seem plausible for that scheme. My problem is when I open the throttle plate all the ohm reading remain constant. Nothing changes. I've opened the plate by hand and also with power. No difference. I feel like the answer is staring me right in the face and I'm missing it.

Suby-EThrottle_zpsc2f24c1d.jpg

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Hi,

I am still looking into this.

The information I have found so far contradicts what I have stated in my earlier post of a typical DBW TPS MAIN and SUB response when testing.

I have found so far, but still not 100% sure of information accuracy,

TPS MAIN CLOSED VOLTAGE = 0.6 V.

TPS MAIN OPEN VOLTAGE =3.96V WOT.

TPS SUB CLOSED VOLTAGE = 1.48 V.

TPS SUB OPEN VOLTAGE = 4.17 V WOT.

DBW MOTOR CONTROL FREQUENCY IS 500 HZ.

Do you still have the factory ecu connected etc, so you can repower it and test the voltages as I have supplied.

Regards

Dave.

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I wired in a AAA battery to P3 and P5. Battery voltage was @ 1.61v. I then checked the voltage at P6 and P4. They were both around 1.56v. Seams plausible. But again, when I open the throttle plate there is no change in those voltage readings.

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Dave - the wire colors are as follows:

P1 = Green

P2 = Yellow/Green

P3 = Blue/White

P4 = Light Green/Black

P5 = Pink

P6 = Light Green

I was at my Granddaughters place tonight and remembered that her Subaru has DBW. So I borrowed an Ohmmeter and did some checking. The pinouts all showed the same readings as my throttle. Furthermore, opening her throttle resulted in the same thing... no change in values. This leads me to believe there is nothing wrong with my throttle. The flaw appears to be in my understanding of how it's supposed to work.

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Hi,

what if you measure ohms between P3 and P4 as one input and then across P5 and P6 as the second input.

2 PINS = POWER + and - for the motor.

2 PINS = TPS MAIN and SENSOR GND = P3 and P4 ??????

2 PINS = TPS SUB and SENSOR GND = P5 and P6 ??????

Regards

Dave.

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2 PINS = TPS MAIN and SENSOR GND = P3 and P4 ?????? = 3000 ohms

2 PINS = TPS SUB and SENSOR GND = P5 and P6 ?????? = 173 ohms

Those do not change when opening the throttle.

I've tried every permutation of ohm-ing the pins, with the exception of paralleling pairs of pins. Not sure if you're asking me to do that?

Does anybody have an e-throttle that behaves differently than what I'm seeing?

Thanks,

Ron

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Hi Ron,

have you tried testing the TPS outputs with the 12 volt + and - hooked up.

Also I have not explained myself properly before, we have the motor + and - which you have worked out.

So that should leave

1 pin for 5 volt ref

1 pin for sensor gnd

1 pin for TPS main

1 pin for TPS sub.

Regards

Dave.

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Hi Ron,

this is very strange behaviour.

I have no explanation for you. :oops:

Do you own a scan tool that you can connect to your grand daughters car and monitor the tps sub and main as you open the throttle.

You can buy these universal readers for around $60 these days.

I have attached a pin out of the throttle pedal for you, but I cant seem to get one for the TPS.

Regards

Dave.

post-1099-143450214867_thumb.gif

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Some throttles use a contact less setup that requires them to be powered to see a varying voltage.

Subaru happen to be one.

Your best bet will be to confirm the pins off the running car.

You need to find the ground and 5 volt supplies.

Then check the voltages off the remaining pins which you can do on your throttle by manually moving the plate.

TPS Main should always be the one that spans the wider voltage range and continues to change through out the full travel.

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Thanks Simon,

I may be able to confirm the running car this week.

I was suspecting something like this may be the case, which is why I tried the 1.6v battery. Hypothetically, if I applied 5v would I be able to see the change?

Thanks again,

Ron

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Success!

5V did the trick. I got a 4.31v to .69v swing on one TPS channel and a 3.43v to .56v swing on the other. Both of them were full range and same direction (not opposite ramp i.e. Ford)

The pin-outs align with other common Denso throttles. Using my picture above, they should be as follows:

P1 = Motor+

P2 = Motor-

P3 = Sensor Ground

P4 = TPS Sub

P5 = +5v

P6 = TPS Main

Thanks for all the help guy's.

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