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I will be doing this so i can pass inspection. SInce i have a jdm swap, i can plug in a usdm obd2 and finally pass inspection.

Am i right or wrong?
 

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Okay, so I am repinning a harness from Aristo, to US ODBII and the adapter I planned to use, is not gonna work. So I am going to connect directly to the bluetooth ODBII scanner. If I was to connect the four individual wires, this is how they'd go.... Right?

Edit: The top pic is for the OBDII receptor at the dash (female), the bottom is the scanner which would connect to it (male). Basically I am bypassing the dash adapter and going to wire to harness signals, from the pics in the 1st page of this thread.


 

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Okay, so I am repinning a harness from Aristo, to US ODBII and the adapter I planned to use, is not gonna work. So I am going to connect directly to the bluetooth ODBII scanner. If I was to connect the four individual wires, this is how they'd go.... Right?
Those pictures are the exact same. You are just looking at one of them backwards and upside down. I'm not 100% sure JDM ecu will work but you can try. I heard they don't have OBD standards over there.
 

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Thanks. Yeah, I had a cable with a female adapter to the scanner, which I was going to wire into the harness. Now, I will have to go directly to the scanner and just wanna get the wires pinned up.

I was on JDM TT/Auto ECU, but now changing over to US OBDII/6-spd ECU in the MKIII Supra. I also plan to use the MAP ECU in the new setup. Basically plan to display some of the CAN data on my tablet (a virtual guage pod).
 

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For all you guys doing this swap. What about going from OBD2 to a OBD1? Anything needs to be done that I am unaware of for this?
 

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Directly soldered the ECU wires to the terminals on the scanner and we have lift-off!!!

Will boost actually be accurate with that? I thought the purpose of a Boost Cut Controller was to fool the ecu into thinking the car is at a boost level below where boost cut would normally be. Am I wrong in this? I'd imagine you'd have to read boost pressure direct from a sensor and not from the ECU signal after BCC to get an accurate response
 

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It was just a sample screen. I am also using a MAP ECU and and ECUMaster ECU in the near future (for the MAP pressure, wideband, etc). Boost and temp gauges are on my A-pillar.
 

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Okay, so I have the wideband pumping the O2 signal to the stock ECU and seems to be running fine. However now have codes P0141 and P0135, both are "O2 Sensor Heater Circuit." How do I resistor/ground them so that I get no more CEL?
 

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Discussion Starter · #131 ·
Did you complete this step?

2) On OBD2 cars there an additional ground wire that's not present on OBD1 cars. Not having this ground wire causes the primary O2 sensor heater to not function. This will prevent the car from entering closed loop operation when there is insufficient heat from the exhaust gas to keep the sensor at operating temp. This happens when the car is cold or idles long enough (4-5 minutes) for the sensor to cool off. It can cause the car to run very rich at idle. Adding the groundwire to the ECU harness fixes the problem.

How to get the primary O2 sensor heater functioning:
Since there's an additional pin needed for the new groundwire you will have to find one to use. This will require you to either cut a wire off of the ECU harness or find a donor pin from another harness. I used the pin from TE2 (E10-19) which is not used on OBD2. On OBD1 it's used for the special diagnostic test mode.

On the ECU wiring harness remove the yellow protectors, they pop off with a small screw driver. Remove pin TE2 (E10-19). It's a pink wire with a green stripe. To accomplish this take a small safety pin and carefully push up the plastic tab that holds the pin in the harness and lightly pull on the wire on the other side of the connector. It should pop right out with a slight tug. Cut the wire a couple of inches away from the ECU connector.

Insert this pin into the new ground wire location E03 (E9-78). Lengthen the wire so it's long enough to reach to a suitable ground point. I used the mounting point for the trac ecu. Attach the wire to the ground point.
 

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Pretty sure I did... I'll double-check though. Copy/pasted from my wiring map/notes below. It may be that the wire came loose from my "common dash-ground" point.

78 E03 Added new pin/wire for ODBii ground Ground to dash somewhere

EDIT: This wire was loose after all. I must've accidentally pulled on it, when chasing down the Cam Position "A" circuit error (which I now still have after replacing the connector) More troubleshooting on that one tomorrow. MANY THANKS for the reminder - sometimes issues' fixes are unbelievably obvious, if U can just take a step back.

The other error that just came up when recently testing for drive-ability was the speed sensor error. I don't think it matters much, but I'm trying to remember how to install the W58 VSS into the R154 and use it for the Apexi R/SM and ECU signals.
 

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For all you guys doing this swap. What about going from OBD2 to a OBD1? Anything needs to be done that I am unaware of for this?
I've heard "backwards compatible," regarding CPS circuits and other pieces. I plan to double-check soon tho, since I have an OBDI ECU available as a spare/backup. I'll have to look, but don't remember changing any power wires/signal which would short anything out, so maybe I'll put the OBDI ECU on there and see what happens.

EDIT: http://www.supraforums.com/forum/showthread.php?550841-Will-and-OBDI-ecu-plug-into-an-OBD-II-harness

Looks like it should work without modification. Hopefully someone with direct experience can chime in.
 

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Checked yesterday...OBDI ECU works, but it idled lower and just seemed to struggle. I got a code, but did not check, assuming it's the CPS code that I'm getting with the OBDII ECU.
 

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Hi,

I put an OBD2 ECU in my MKIV of 1996 (OBD1), but by making a check, I have a code error 1630p powertrain.
And I have the green light " TRC " which ignites when I start the engine.
And I also have the light "red triangle" which also ignites !

What are the solutions for these problems ?

Thanks for your help

ptauss
 

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Hi,

I put an OBD2 ECU in my MKIV of 1996 (OBD1), but by making a check, I have a code error 1630p powertrain.
And I have the green light " TRC " which ignites when I start the engine.
And I also have the light "red triangle" which also ignites !

What are the solutions for these problems ?

Thanks for your help

ptauss
Please, nobody to help me ?
 

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You lose function of the traction control when you switch from OBD1 to OBD2. The systems are different. That's why you are getting the code P1630, and TRAC OFF lights up.
 

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You lose function of the traction control when you switch from OBD1 to OBD2. The systems are different. That's why you are getting the code P1630, and TRAC OFF lights up.
Finally I have a concrete answer with my problem. Thanks very much
For the master warning light /!\ in red square, it's also switched on because of that ?

Thanks for your help

@+
 

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Finally I have a concrete answer with my problem. Thanks very much
For the master warning light /!\ in red square, it's also switched on because of that ?

Thanks for your help

@+
Yes, the diagnostic trouble code P1630 will trigger the /!\. I also get codes for my HKS 264 cams, and occasionally the rear O2.
 
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