I own a 1999 SC300 and want to do W58 5-speed swap in the future. Even though everything should basically fit, I still have one issue that eats at me: the ECU. I know for a fact that the check engine light will turn on, so I would need this issue resolved because I live in California, and California is a real pain when it comes to smog checks. I want to know from all the people that did these swaps how they overcame the check engine/ECU problem, especially from those that have done swaps in 97+ SC's. I know one possibility is to use a transmission simulator that Phoenix Tuning makes, but I still have my doubts about it. I also wonder if using a 1997 SC300 5-speed ECU would bypass this problem. I would like to explore ALL the possibilities of resolving this issue before committing to this swap. Sorry if this such a long post, but I gotta be 100% sure before trying to get everything together.

 

97 ECU won't work with yours, the 99's have a VVTi engine, 97s did not have VVTi so the ecu is not compatible.

 

Ok so the SC's ecu won't work. What if were to use a 1997+ Supra ECU? If I recall correctly, their engines were equipped with VVT-i after 97.

 

Yeah ive had these same questions before. i kinda gave up and started my NA-t setup first and planned on coming back to this after i finished. i havent heard anything about the simulators and might have to look into that. what about it didnt you quite trust?

ive thought about VVT-i supra ECU but dont know about it. im pretty sure phoenix tuning could get it to work with the harness but it could get costly maybe.

Im pretty sure, correct me if im wrong, but i think the AUTO 98+ SC300 VVT-i ECU is the Same as the 01 IS300 VVT-i. So i didnt know how similar the 5spd ECU would be to are cars and if that would work.

Most people that have 98+ SC's havent did the swap and if there car is 5spd they have done a swap with the ECU for that Motor and Tranny. At least i cant find any.

Theres also Full Standalone ECU but to people who just want to W58 and nothing else it might not be worth it.

Someone please chime in to help!

 

hey guys,
i just bought jrm87's 99 SC300 that has the 5spd swap completed, but the shop that completed the swap didn't do anything with the ECU (the CEL is on for 6 transmission codes!)
we have emissions testing here in Nashville TN (OBDII plug-in test) so i am going to tackle this problem ASAP.

 

hey friends,
so i had 6 CEL codes from the 5 speed swap,
i put resistors in and got rid of 3 codes.

the 3 variable voltage solenoids are going to be a problem.
i took the valve body out of my spare Chaser auto trans (similar to the sc300 auto trans) so i'm going to just hook up those solenoids out of the spare trans and see if that makes the 3 remaining codes go away...
the 3 pain in the *** codes are:
p1755 Linear Solenoid For Lock-Up Control
p1760 Linear Solenoid For Line Pressure Control
p1765 Linear Solenoid For Accumulator Pressure Control

i'll post the other 3 codes (that i got to go away by adding resistors) as soon as i find the note card i wrote them down on

 

I didn't get any codes on my 95 when I did the swap. I did provide a V2 signal by installing the auto V2 sensor at the traction control sensor location of the W58 - not sure if you need to do this or not . And I did install resistors for the solinoids. The O/D and/or the ECT lights did/do flash (can't remember which) I pulled the bulbs, but I had no CEL.

 

you didn't have a CEL because only the 97+s have the OBDII system. and IIRC, only the 98+s have the 5 spd auto trans.

good idea on the v2 sensor though (vehicle speed #2?)
that is required for the cruise control as well, right? this may be why mine doesn't work.

 

lol so have you tried plugging in the 3 solenoids and hiding them somewhere. that would be hilarious if that worked.

 

i actually was going to try that, but the solenoids in my Chaser trans are different (and have different colored wires) and the Chaser trans is a 4 speed auto, not a 5 speed.
i took the valve body out of my chaser trans just so i could do this. lol.

i think all the valves work in a similar way, but i dont have a chaser FSM so i can't be sure they are variable voltage like the 98+ SCs are.

 

well i got two of the codes GONE by plugging in two of the variable voltage valves from the old transmission. (this trans only has two!)

now i just need another one.


so ali, the answer would be YES; plugging in the following will get rid of the CEL codes when you remove the auto trans on the 98+:

shift solenoid 1 ~15 ohms (p0753) i just used a resistor here to ground
shift solenoid 2 ~15 ohms (p0758) i just used a resistor here to ground
SLU valve ~5.5 ohms AND ~5 volts (p1755)
SLT valve ~5.5 ohms AND ~5 volts (p1760)
SLN valve ~5.5 ohms AND ~5 volts (p1765)
trans temp sensor ~200 ohms (p0710) i just used a resistor here

boom

 

does your cruise control work?

i do not have the v2 speed sensor plugged in. i am assuming this is why my cruise control does not work! (but there's not CEL for the v2 sensor)

 

The OEM 5speeds cruise control only works in 5th gear. Doubt it will work with the auto ecu.

 

i thought it went by speed.

 

are you sure about that?

and btw, there was no OEM 5speed in 98-2000.