Ali SC3

iTrader: (10)

I did see that IDL2 is conencted to the trac control ecu also in the wiring diagrams, so it may be related to that. I would start with jumping IDL2 with the 1M ohm resistor as described above before we go about messing with the trac ecu side.

BuffNStuff

From what I am reading, pre 1997 supras had a whole mess of lines and a TRAC pump that had to be removed do delete the traction control, along with 2 resistors that go into the plug. For 1997 supras, there are no lines or TRAC pump, just a small trac ECU, but I cannot find information on how to delete it.

Also, I did put in the 10k ohm resistor (correct me if I am wrong, but in the quote you posted from the other forum, it said to use the 10k resistor between "1 and 3", so doesnt that mean the IDL needs a 10k ohm resistor and the 1m ohm goes in B42?) in a jumper wire between b41 and b63. I did not check if b63 already had 5v to it though. Maybe that is why it didnt change anything. ill go check right now.

*Just checked, and the b63 side of the jumper wire is reading 0v. I dont understand why there needs to be a resistor in the jumper wire that drops the voltage from 5 to zero if there isnt any voltage in that wire to begin with.

Ali SC3

iTrader: (10)

was there a wire already there? Thats odd if there is a wire there already. The values should be close to 0 but not 0.
If there was a wire there I would probably remove that wire and then put the jumper 5v to the resistor and then a new wire to that pin, if you connect it to the existing wire that is reading 0 it could be a ground that could be throwing off the value the ecu wants.
remember the 5v was too high of a value, and a ground would be too low of a value, so it could be throwing it off.
seems like odb2 made it so you can't just jump 5v or ground to make things happy, actually needs the right range of voltage but that just means a resistor which is not much harder to do.
What puzzles me is why your harness had the blue/red wire to the VTA2 instead of nothing at all, same for the wire if there is one on the IDL2, do you know what color the wire is going into B63?

*edit* I just had a thought, maybe they put power and ground there on the signal wires so that if someone were to plug in a new 2JZGE ecu with trac control it would trip all the codes for it, telling you its not the right ecu cause your car doesn't have trac. Its just a simple of way to make it show up on the scanner. I didn;t read this anywhere it is the only thing that makes sense to me, as otherwise they would have left them blank but I feel like that would trip codes too, maybe not as well though. Using the resistors should help, but you can;t use the ground wire on the b63 to put a resistor on, you have to jumper from the b41 with the resistor to that pin and disconnect the existing ground wire. you can even cut the existing wire and connect it to your jumper wire. I bet the wire is brown or black in color.

BuffNStuff

I unsoldered the wire that was there and now only have the wire with the resistor going from b41 to b63 and I still have the 1630 trac code. My scanner lables this code as a "Grey code" and it says this code "may only be cleared after 'N' drive cycles"

The wire is either green or brown. (I have a type of colorblindness, I know I know, not optimal for this sort of project.)

I just checked the voltage on both sides of the resistor and on the side that connects to B41 it is 5.09v, and on the other side of the resistor it is now showing 5.4v. Shouldnt the resistor make the voltage lower on the b63 side??

BuffNStuff

This is the wire that was connected to b63. Looks kinda green to me?



I did some digging, and I am not sure if this only applies to pre1997 supras or not, but it seems people just "pull the TRAC fuse". They sat this gives them a check engine light but I don't see anywhere where it says their car runs poorly as a result.

I would assume I just need to find the voltage required by the ecu from the TRAC ecu that says it's not turned on and wire in the correct resistors.

BuffNStuff

I found these on 97supra.com. It looks like I SHOULD be able to just put resistors in the 4 wires that are supposed to go from the ECU to the TRAC ECU. Only thing is that I have no idea what value of resistors should be put in each wire.

Ali SC3

iTrader: (10)

These are the 4 wires you will need to sort out for that code. Notice the code says open or short in the circuits only for Ect and efi +/-.

Ali SC3

iTrader: (10)

You shouldn't get a check engine light for it, just the code if you pull it. That wire is brown by the way most likely was a ground.

BuffNStuff

Any idea on what resistors I should try? or if you think all 4 of them need resistors? I assume I need to make a jumper wire with the resistors and jump them between the correct pins, as opposed to wiring in resistors into the wires currently there already.

BuffNStuff

I guess a good place to try first would be pins A39 and A40 because they are VT01 and VT02 and they are supposed to connect to VTA1 and VTA2 on the TRAC ecu. As you can see there are no wires going into these pins at all so I figured that would be the best place to start.

*Edit* I noticed my wiring diagram doesnt reflect the same pins as yours. Yours says I need to look at pins 26 & 27 and 13 &14 (Those pins are also blank on my harness)

BuffNStuff

I really hope this wiring can be done. I'd hate to have come this far just to have to ditch everything for an expensive standalone unit. The cheapest i found a traction control module was $1800!! That is INSANE.

On 97supra.com, it says that the failsafe operation for the p1630 code is "subthrottle valve fixed at fully open position." Is this what the failsafe will CAUSE, or what puts it IN failsafe mode? Because the way I see it in my head, if this code causes the subthrottle valve to be fixed open, wouldnt that do nothing to how the car would run? Seeing as how I dont have a subthrottle valve?

I also found this; http://www.scribd.com/doc/97650348/T...Control-System

"When either rear tire begins slipping during acceleration,TRAC system pulses the rear brakes and throttles back the engine toregain traction. The driver has the option of activating ordeactivating TRAC system. Located on the instrument panel is a TRACOFF switch and TRAC indicator light.Pressing the TRAC OFF switch turns off TRAC system. PressTRAC OFF switch again turns on TRAC system. TRAC system is alwaysoperative after engine start. When TRAC system is operative, the TRACindicator light blinks. When a malfunction occurs and ABS/TRAC ECUsets a diagnostic mode, this light blinks self-diagnostic results.An actuator is fitted to the throttle body. The TRAC actuatorcontrols sub-throttle valve according to signals from ABS/TRAC ECU,thus controlling the engine output.Sensors fitted to the sub-throttle valve shaft convert theopening angle to voltage signal and send signal to ABS/TRAC ECU viaengine and transmission ECU, controlling throttle position signals.The TRAC system brake actuator consists of a pump andaccumulator assembly which produces regulated fluid pressure in thedisc brake calipers of the right and left rear wheels separately. Thisfunction is also controlled by signals from the ABS/TRAC ECU.Brake fluid pressure in the right and left rear wheels iscontrolled separately in three control modes (pressure increase,holding and pressure reduction). This process is controlled bysolenoid valves, pressure switches and sensors.If a malfunction occurs while the TRAC system is inoperative,the ECU immediately turns off the TRAC throttle relay, TRAC motorrelay and TRAC brake main relay.If malfunction occurs while TRAC is operative, the ECUcontinues control (stops the control or fully opens the sub-throttlevalve depending on the types of malfunction). If TRAC becomesinoperative, the engine and brake systems operate like vehicleswithout TRAC regulated. The ECU continues normal control even when a malfunction occurs."

So it SOUNDS like I should be able to drive along just fine? And I wouldnt imagine I would fail emissions for a traction control code.

Ali SC3

iTrader: (10)

Yes those pins should be blank on your harness since you don't have a trac ecu at all. I am guessing the code did not go away. You wouldn't get a new one anyways I would check supraforums they probably are very inexpensive tons of people actually remove them from their cars.

It will not affect how the motor drives, it is just a trac code. as the description says it will just turn off the trac stuff when that code is up, My older SC with trac when the trac light came on only thing that would happen is the trac wouldn't work, engine and everything else worked fine. Even has a separate light from the check engine light, but odb2 they condensed it all into one. I would think it wont even light up the CEL if its the only code.

Yes it goes to failsafe and that is fully open, meaning it does not interfere with engine operation at all. normally the trac works by closing the second throttle body when your wheels slip to cut power to the motor. In the fully open position, the trac essentially does nothing which is the same as disconnecting the connector to it, or pulling the trac fuse on a car that has the full trac system.

It would just be adding it to get rid of the code coming up, and a standalone does not display any codes at all so that would not help you any better with emissions. I would get rid of all the other codes and see if they even care about the trac and auto codes, I have a feeling you may still pass they generally are looking for emissions readiness codes but I am not 100% on that, but its worth a try before you move on.

I would think that there is a way to make that code go away even, but it looks like we may actually be the first to try or document it, so that just means it will take a little bit longer but I would think its possible to get rid of that also. lol If you had trac this would have been easier, most of the auto's do I am surprised you don't have it.

If you see page 21 in the link in the chart at the bottom, it sort of says you can pass if you have a pending code, but it does not light up the MIL
http://www.smogcheck.ca.gov/80_BARRe...08-09%20V3.pdf
according to this diagram it should not light up the MIL for this code.


My guess is that you can leave the pending trac code and not really have any issues driving wise or emissions wise. I wouldn't bother fixing it till they tell you that one is a problem then. all the literature is pointing to it shouldn't be a problem if the MIL is off when you go in. I know the aristo ecu's have trac and my car did not come with trac and it still drives like butter. I am sure if I had a trac light on my cluster it would be lit up.

BuffNStuff

Okay cool. Ill move on to trying to adjust the TPS to fix my hunting idle. I gotta do some research to see what I need to do for that. THANKS!!

BuffNStuff

Is it 12v or 5v power into the resistor to the pin for the VSV?

*Found it. It is 12v power (PIN A31) to the 1kohm 1/2 watt resistor, into pin B40.*

I got both the EGR VSV and the IACV VSV wired up and those codes are gone!!

All that remains code-wise, are the 2 transmission codes, and the traction control code. THANK YOU.

I tried adjusting the TPS but I am scared. When I rotate it, it does change how the car idles. Either it will slow down or rev higher and faster. I am scared because it starts to go really lean after about 20 seconds of this surging. I dont really have enough time to fiddle with the TPS before I have to run and shut the car off.

SCereal

iTrader: (4)

You have the TPS installed correctly? There's a trick to it as I recall. I think it's orient it clockwise past where the screw holes line up, put it on then turn it counter clockwise until you can screw it in, adjust from there. That way it catches on the tab in the correct orientation. there's a video on youtube about it.

Just a thought since you having trouble with it and I recall reading about it being tricky.