Hey guys, I just did an auto to R154 swap on my 96 SC. I had several check engine lights after the swap was finished. Most CELs were removed thanks to this thread

That was a pretty simple fix, just replace the solenoids that were lighting up CELs with resistors

Then came CEL P1780...also "fixed" here

This was for the Park/Neutral Position(PnP) Switch...just needed a relay to have both PnP switch ON and P at the same time to start the car...then switch to D and turn OFF PnP switch to drive normally and keep P1780 off.

Then came CEL P1700 that only 96 and 97 SCs have!

This is for Vehicle Speed Sensor #2 (VSS2)...
I have the VSS2 plugged in but since theres no place to plug it into the transmission, it just hangs under the car and doesnt send any signals to the ECM

Anyone have any suggestions? maybe find a way to feed the ECM speed signals? Stockhatch? Cartmill?


UPDATE: Potential fix for P1700 here:
https://www.tacomaworld.com/threads/....629100/page-3

 

As you can see, by keeping PnP switch OFF, CEL P1780 doesnt come on, but since its off...conditions for CEL P1700 are met and the OBDII detects no signal from VSS2, so I get CEL for that

If I drive with PnP switch ON, I get P1780 but not P1700
If I drive with PnP switch OFF + D, I get P1700 but not P1780

 

You can see that the rectangle at the top shows that Pin4 jumpered to Pin7 gives P

and

Pin4 jumpered to Pin9 gives D

all this jumpering happens at the biggest connector disconnected from the Auto transmission

this connector also has Pins to jumper the PnP switch ON or OFF

 

This is the closest solution to fixing P1700 by giving VSS2 a signal , but I dont know if the signals produced give an accurate speedometer reading or not...and where would I get one of those plates

maybe I should just just get a 5 speed ECU...

 

Picture above was posted by another member

 

If you missed the thread this is the link

 

Thanks, that toothed wheel looks like it might work...Im trying to find more info about it

 

You have one of two years that have an available plug and play manual ecu. I would get one.

 

^i am with stockhatch. just pay 100 bucks for an 5spd ECU and you don't have to mess with anything else

that driveshaft trigger wheel setup is pretty slick though!

also, if i left my relay setup hooked up, i would get the Park/neutral safety switch CEL code after a drive cycle.
i ended up just pulling the relay setup OUT, not tricking it into thinking it's in Drive or Park (so it basically just thinks it's in neutral all the time) and the CEL codes went away forever.

your 96-97 thing is different. those are the "in between" ecus. OBDII is a pain in the ***.

 

Thanks guys, I think Ill do that and just get the 5speed ECU...

 

Cartmill, when you make the car think its in neutral full time, does your cruise still work(at least up to the speed limiter issue)?

 

I've been looking for a 96-97 manual ecu for awhile. Good luck!

 

Doesn't the ECU judge the car to be in D and not Neutral, when no signal is sent to the ECU? (Which is what Cartmill did by ripping out the relay, right?)

 

Have you tried looking for a supra computer? 232 1996 and 120 1997 manuals. Fat chance you'll find one of those computers out of a Lexus SC300

 

I think you can go through auto parts stores to get reman ecus. It may cost a lot, but it may be the only easy option.