RandC

I'm finishing an R154 swap in my '99 SC400.

I'm using cartmill's parking brake switch relay mod to activate the P and D wires. The relay is activating the wires properly.

The pin 4 wire (Yellow/Green stripe) from the selector switch supplying power to pin 30 on the relay.

The pin 7 P wire (Black/White stripe) is connected to pin 87a and is hot when the parking brake lever is lifted.

The pin 9 D wire (Green/Yellow stripe) is connected to pin 87 and is hot when the parking brake lever is down.

When I turn the ignition switch on, the P light comes on when the brake lever is lifted. The BRAKE light on the dash also comes on. The D light does not come on when the parking brake lever is down.

The engine will not crank. I have CEL code P1780 (Park/Neutral Position Switch Malfunction). There are no other error codes.

The pin 4 wire is also supplying power to the reverse switch on the transmission. Backup lights are working. Disconnecting the reverse switch does not solve the problem.

Thanks in advance for any suggestions.

xtra

Bro, ditch the relay system.
Mine is a 97 OBD2, I just bypass the neutral switch and hard wire the reverse to the transmission. I have been driving my car for a few months now and no CEL comes on.
I had it wired up using a relay to drive in D mode and in L, I have notice no performance gains, there was no changes what so ever except the CEL would constantly throw code P1780 every time I restarted the car. Yours is a 99 with the VVTI and I don’t know if driving in N will affect it any but it didn’t in my car.
I hope this helps.
Correction: The CEL light came twice actually but it was after not driving my car for a few weeks and the battery had drained, Boosted the car and resetted the ECU and no more CEL. I since then leave it connected on a trickle charger if I don’t intend to drive it for some time.

RandC

I can't make the engine turn over. I turn the key and nothing happens. The car won't start unless the ECU senses that the transmission is in P or N. The P is lit up. The car won't start.

Reverse works fine. It is hardwired. I can hardwire the drive, but I get no D indication. The ECU only looks for Park or Neutral for starting permissive.

How did you wire the Park or Neutral? Are there any other wires from the shift position switch that need to be connected?

Super Frustrated!

scENFORCER

Post #12 in this thread says to simply jump the NSS..
https://www.clublexus.com/forums/per...mechanics.html

I'm going to be doing this same swap on my '99 and will be curious what issues you come across and how you solve them. I'm bookmarking this thread for later use.

RandC

I've already read as much info as I can find and thought I was completely prepared...

scENFORCER

This thread might also help..
https://www.clublexus.com/forums/sc-...-finished.html

xtra

Ok , In the transmission harness, get a 10 amp fuse and bridge the 2 plug together. The fuse will only go into 1 location if your car is harness is the same as any other previous year SC.

Try that 1st and let us know it it starts.

RandC

I'm sorry, but that does not make sense to me.

I unplugged the wiring harness from the transmission. There is the hydraulic control and transmisssion oil temp connector. I made a dummy rig and connected to this. It works. There are no CEL codes there.

There is a speed sensor connector that reads the speed of the output shaft, for the cruise control. My transmission has an output shaft speed sensor, with 4 pulses/rev, so I expect that it will be 100% compatible. I had to run a third wire for a ground. It is grounded to the chassis

There is another connector for the input shaft speed. This is not currently connected to anything (in fact I cut it off).

The transmission gear selector (Park/Neutral Safety Switch) connector has several wires, as shown in the several wiring diagrams posted in various threads here. I have the factory wiring manual and have studied it extensively. There is no fuse anywhere in the wiring harness that I am aware of. Are you talking about the main fuse panel?

There are 2 wires in the middle of this connector that I am unsure about. They are bigger wires (18 ga?) than all the rest. They are not connected. When the automatic tranmission is in Park, there is a resistance of something like 200 ohms across these terminals. I'm not near the car, so I don't know the actual value. Do these wires need to be connected through a resistor?

Thanks!

RandC

I think we're talking about the same 2 wires. You installed a 10A fuse across the terminals for the G/R wire and the B/W wire in the connector?

I saw these wires mentioned in cartmill's thread, but it was never clearly specified.

Ali SC3

iTrader: (10)

I am pretty sure all you need to get it to start is to jump 2 wires on the gear selector connector I think you are talking about. no resistor needed. you could use a fuse I guess but to test it just jump it with a piece of wire.
there was a picture in one of these threads I will update the post if I find it.

scroll down on this page there is a picture
https://www.clublexus.com/forums/per...-lights-6.html

also see post 12
https://www.clublexus.com/forums/per...onversion.html

xtra

Exactly, i always like to test things before cutting.

Sorry for the confusion.

RandC

Yup. That was it.

I saw that diagram in another post and missed the pin 5 - pin 6 connection on the Park-Neutral Position switch.

It started right up, with no error codes.

Awesome! Thanks guys!

I'll post some build threads soon.

scENFORCER

Curious how much this swap cost you? And how long did it take?
Also, as in one of the other links I gave above, the owner experienced a slight hesitation going from 1st to 2nd. Are you expieriencing the same?
Sorry, I know you literally just finished the swap, but like you I want to have all the info possible before I jump into this, lol.

RandC

I'm building a road and track car, so I wanted it bulletproof. It's probably more so than I need.

I found a '99 JDM R154 that supposedly fits the SC300. It was very expensive, but exactly what I wanted and in superb condition. I decided to go through it and do all of the Marlin Crawler mods, so I disassembled and installed the thrust washer, bearing retainer and shift forks, including the Drifmotion 3-4 fork. The transmission must have been in a TT Supra with an older driver that liked how it looked. It was almost new inside and smelled sweet. The rebuild went smoothly.

I didn't buy a kit and relied on too many sources for information, so I had to reinvent the wheel and ended up with a fairly unique set of solutions, but spent way too much time taking steps backward. I machined my own flywheel, starting with an early Toyota V6 flywheel and removing a lot of material. I think it was 16.8 lbs when I was done. The 1uzfeswapkit.com flywheel is a great value. Buy one! He didn't pay me and doesn't know who I am I also got a lot of input and parts from Driftmotion.

I thought I should put a 2JZ-GTE clutch and pressure plate in, but they are pull-type and I needed a push-type. Another foray into the unknown. It only took a couple of weeks to sort it out... Buy an ACT 3S-GTE HD clutch and pressure plate (sold as a W58 clutch, but works perfectly with an R154).

I used a RAM hydraulic throwout and had to make a custom adapter plate - another can-o-worms. I bought a Howe bearing after the fact and didn't like it. It only took a week or so to sort it out. I'm stoked with the result.

You'll see people bragging about 1-2 day swaps. Don't plan on it, unless you buy a kit, spend the money and do it the easy way. Not to say it's a bad idea, but the wiring alone took...
Never mind, I'm not going to say how long it took.

It was expensive and took a long time.


I am doing some significant suspension mods, so I can't drive it yet. More on this later.
I'll have power to the D wire on the selector switch, so the ECU should be happy and driveablilty should not be affected.

More to come, in other threads...

KahnBB6

iTrader: (5)

^^ Having done 1/4 of this the easy way on a JZ car I agree. I believe everything you've written above. It must be a good feeling to have it together now, however.