landins13

I am running a VVTI 1JZ with a toyota R154 transmission and I wanted to have a working OEM speedometer. I knew i would need a Dakota Digital signal converter but i didnt realize that there is almost no information on how to do this anywhere on the internet.

After spending about 3 weeks compiling wiring diagrams and doing research I was able to get all the information I needed to do this properly and with everything working as it should.

Now I of course had to make things harder on myself because I wanted to swap my analog cluster with digital HUD cluster but that does not effect the overall information or any of the wiring. It just made things a pain for me.


Disclaimer:
This is not the cheapest way to do this but in my opinion it was the only way i would be comfortable. Also there are plenty of other threads out there showing how to remove a cluster so i did not clutter this up with info on doing that. If you are not comfortable de-pinning oem connectors or running your own wiring, find someone who is or have a shop do the install. i created this thread simply to compile the information it took me a good bit of time to sort out.

To start the first thing you will need to do is identify the type of R154 transmission you have as well as what speed sensor is in it.

If you have an older R154 you more than likely have a mechanical sensor. this is not a problem since you can purchase a part from Marlin Crawler that will convert the signal to a digital one that can be used. If you have a newer R154 you can use the Rear speed sensor that is located on the right side of the transmission near the driveshaft.


Some of the options look like these:


This is the rear ABS (Speed) sensor on the newer R154 such as mine.



The first big concern with wiring these is that 9/10 times your R154 will not have a connector and pigtail on the speed sensor. After pursuing it several different ways I was eventually able to find a parts guy at a local lexus dealership that was able to get me just the connector and 100mm leads for it. Every other dealer i talked to told me i had to buy a $2000 engine harness or they gave me the wrong part number.

the Marlin Crawler unit as well as the OEM Rear Speed sensor both use the same 3 pin connector. This connector is the same on used on the R154 as well as W58 transmission found in the SC300 and IS300. The whole point in using it is that its weatherproof and plugs straight in.

These are the part numbers to order them:
90980-11143
82998-12440

This is what you get:




In addition you will need a converter box from Dakota Digital the unit you want is the SGI-5. You will need one of these to run most aftermarket speedometers as well.


Once you have these things the next portion to address is the wiring itself. you can use the oem wiring harness if you choose to. Personally I made my own harness to make it easier to trouble shoot.

WIRING

I made this lead about 3' long and located the control box in my arm rest and ran the wiring through the top of the excess space next to the shifter straight down to the VSS

The wiring is as follows:

VSS Connector Pin 3: Signal to Input on SGI-5 (-)
VSS Connector Pin 2: Ground (-) to Sensor Ground on SGI-5
VSS Connector Pin 1: 12v Switch power from fuse box

From the SGI-5 the wiring is straight forward, just run wires from the control box to the appropriate sections:




You will use output 1

Output1: Yellow wire w/ Blue stripe on the cluster sub harness
Power: 12v switch power
Ground: Good chasis ground


The last wire you are concerned with is Yellow w/ Black stripe and this is on the cluster sub harness as well. This wire needs the be grounded to the same spot you run the ground wire for the SGI-5 Unit

This is the harness I made already wired into the SGI-5, I made a point of using different color wires so that i wouldnt mix anything up and this worked 100% the first time i plugged it in.






After you re-install your cluster you will need to calibrate the SGI-5 so that the speedo reads correctly.It seems more complicated than it really is but here is the easiest way to set it.

All switches should be off. Use either a friend driving next to you or radar to make sure its accurate. Personally i downloaded a GPS speedo to my phone and used that. Drive at a steady speed and just use the UP and Down buttons on the SGI-5 until the speedo becomes accurate.

It is possible to set the course and fine adjustments without the car moving but either way you will need to drive the car first to be able to determine what your correction should be. The equation to get this will be:

(Actual speed / Speedo Reading) x Current Ratio = New Calculation Ratio


The end result and goal is an accurate and properly functioning factory cluster.




Quick Reference Parts/Price list:
18 Gauge wire whatever colors/color you want. I used red black blue and white
Dakota Digital SGI-5 Cost =$80-$85
Lexus/Toyota 82998-12440 Cost $15
Lexus/Toyota 90980-11143 Cost $15
Marlin Crawler Speed Converter Cost= $50

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NO HANDS IN PANTS!!