Grande Speedo Calibration

[Troy1]

Hey AB,

Thanks for the info, I will supply that to the auto electrican might help. Cant NSW just adopt the Vehicle Standards Bulletin 14 (VSB 14) then we wouldnt need certification. But would probably still need speedo calibration ADR 18?

http://www.infrastructure.gov.au/roa..._2011%20v3.pdf

The wheel track of off-road four wheel drive vehicles and goods vehicles (MC, NA, NB ADR
category) must not be increased by more than 50mm beyond the maximum specified by the
vehicle manufacturer for the particular model.

Troy

[busha]

Troy1,
We really need to know which model SpeedoHealer 'Cubtronix' had used and exactly on which model Prado.
I have requested SpeedoHealer dealer regarding compatability with my Prado Grande. They are following this up.
I have followed up with Yellow Box. They are completing V5 next week.
Yellow Box are seriuosly looking into Calibrator for Prado Grande 120 as I have provided them with wiring diagram on my Prado.

There are few technical issues which was of interest:
"The signal type being received by the speedometer/
instrument panel/dash. Is it a square wave signal or sine wave signal? See
below.
There are two main types of speed sensors; Hall-effect sensors (have 3-wires)
and variable reluctance sensors (have 2-wires, referred to as ABS sensors).
The number of wires from the sensor is a visual indicator which type.
Hall-effect sensors output a square wave signal from zero volts DC to
+12 volts DC to zero volts DC etc.
Variable reluctance sensors output a sine wave AC signal from -12 volts DC
to +12 volts DC to -12 volts DC etc.
The two different signal types above require a different Box model
to suit/be compatible with the signal."

I will see how this progresses and post on this thread.

I am keen to fit 265x70x17 MT on my Prado but this tyre size is definetely illegal on Prado 120 in NSW without certification and hence the insurance issue.
AB

[Troy1]

Hello all,

I have posted this else where but thought it might belong better here.

Update, well took the prado in and well they plugged it all in and took it for a drive and well after 100m or so dash lights came on and then loss of power as the transmission went into limp mode. :-( tried to different brands of speedo calibrator and had the same result. The auto electrician contacted the company in melbourne who is trying to work on a solution. Apperently they have done it on 2005 models and earlier before with out any issues, although they said after 2006 you cant do it cause the wiring is different and you cant splice into it. Although from previous posts i believe those vehicles are all ready running under so would be running accurate with the 70 profile tyres and would there for not need a re calibration. Apperently my grande being a late 2005 is a high breed between the two hence the issues. Fingers crossed they find a solution. Ill keep you posted

If they cant find a solution I might show them the one on this page and see if it will work.

Troy

[Troy1]

hey cubtronix,

Having issues with mine out of curious comparison what month/year is the build on your grande?

Cheers

Troy

[Peterpilot]

Yellow Box is another speedo correction option. They are based in Bundaberg and say they can do a plug and play harness: http://www.YellR.com/

[bluesman]

What model did you order, from the states, i would like to purchase one as i have just put 275/70r/17 the new Coopers ATZ 3's on my 2005 Grande, and the speedo is out by 5klm per hr, below the actual speed, so like you can not afford any speeding fines.


David

[Peterpilot]

Nice work, I've been pondering how to get my speedo to read accurately with 70 series rubber. I take it that your Grande is an earlier model like my 2004? My speedo reads accurately with standard 265/65/17 tyres. Apparently models after 2007 or so have speedos that read correctly with 265/70/17 tyres.

[cubtronix]

Grande Speedo Calibration Part 3

Ground, pin 2, white/black:



After some insulating, it's time for a test. The speedohealer comes with a bypass plug that allows you to feed the original signal straight through. I plugged this in and went for a test drive to make sure the speedo still works as normal.

Originally it didn't work and I got ABS, TRC, VSC and Check Engine lights on the dash after about a minute of driving. After stressing that I have broken something serious I checked all my connections and discovered one of the joiners from the kit was giving a bad connection. After ripping out all the connectors and soldering all the connections and resetting the faults on the ECU, the second test drive went well. I chucked a scope on the signal too to double check it was what I expected, which it was. Time to plug in the speedohealer. Plugged in with the ignition on I got power to the unit to program in the correction factor. I used the online calculator from the website which gave me a correction factor of +4.8.

Speedohealer installed. I fixed it with the supplied velcro to the ECU unit under the glove box. You only need to remove 1 screw if you ever need to get to it again:



Third test drive. Speedo works, good sign. Got out the GPS for a check and it is reading spot on now.

[cubtronix]

Grande Speedo Calibration Part 2

Now you can see the connectors that I hacked into. The IL1 connector is the top one (the one I covered in red insulation tape).



Now is probably a good time to isolate the battery before you get into the electrical stuff. Looking at the IL1 connector while it is in place pin 1 is on the top left, pin 2 is below that and so on. All the pins that are useful are on the left hand side of the connector.

• Pin 2 - GND (white with black stripe)
• Pin 5 - Speedo pulse signal (pink with blue stripe). There is also a pink/blue in pin 6 but I'm not sure about this one.
• Pin 8 - 12VDC switched from ignition (black with red stripe)

It is worth noting the direction of the signal on pin 5. The male side of pin 5 (which is the one fixed in place) goes to the combination meter in the dash. The female side (the bit you can pull out) goes back to the signal source. Remembering this signal direction will help when connecting the speedohealer. Now for the installation. The speedohealer has 4 wires:

1. Red - 12VDC
2. Black - GND
3. White - Original Signal from speed sensor
4. Green - Corrected Signal to speedo

The installation goes like this:

1. Splice the black (GND) speedohealer wire to the white/black wire from pin 2
2. Splice the red (12V) speedohealer wire to the black/red wire from pin 8 (I wired an inline fuse here to be safe)
3. Cut the pink/blue wire on pin 5 and connect the green (corrected signal) speedohealer wire to the end dangling from the connector.
4. Connect the white (uncorrected signal) speedohealer wire to the other free end of the pink/blue wire.

I soldered all the connections. I didn't end up using the joiners and splice blocks that came with the kit as they gave me some trouble which I’ll get to in a bit.

The 12VDC is taken from pin 8, black/red wire (I ran it through a fuse first):



Corrected and Uncorrected speedo signals. Pin 5, pink/blue:

[cubtronix]

Finally got my speedo reading correctly after fitting 265/70/R17s so I though I would give something back to the PP community and share my experience.

After upgrading the tyres to some nice new Cooper S/T Maxx, I began looking for a way to recalibrate the speedo to compensate for the larger tyre diameter. Like many fellow PradoPointers running 265/70/R17s I found my speedo reading under by around 5%. To my surprise I found most people were happy to tolerate the error, but after my latest impromptu meeting with the kind folk of the WA police force, I decided to get serious about getting it sorted. With the new tyres my speedo was reading 105kph when my true speed was 110kph



Having not had too much luck on PP I consulted the google box, which again didn't really help too much. Eventually I stumbled across a bloke in the states with a 4runner who found a nice solution. He used the SpeedoHealer from www.healtech-electronics.com. It's basically a gizmo that tweaks the speed pulses coming from the speed sensor before the signal is sent to the display. For Toyota's with ABS, traction and stability control, there are speed sensors in each wheel that are fed back to the Skid Control ECU which then combines them all into a single speed signal that is sent to the combination meter (speedometer) in the dash. The trick is to tap into this signal and let the speedohealer work its magic on it. So, I figured I would give it a go and ordered the gadget. They are designed for motorcycles but they offer a universal wiring harness which is what I went for.



From what I’ve seen there are a few different brands available that can do this. I think any of the electrical speedo correction devices will work, the key is putting it in the right place. After digging up some electrical schematics I found the easiest place to hack into the signal was at pin 5 of connector IL1 which is located on the passenger side on the left hand side of the aircon filter behind the glove box.

First remove the wood grain (or equivalent) insert thingy. I don’t think it’s absolutely necessary but it makes it easier to see the glovebox retainer clips. It's just held in with snap in clips so just pull it out gently:



Now remove the 5(?) screws holding in the glove box surround and remove it, there are a couple of plugs that need to be disconnected from the glovebox in the process:



To be continued; image limit reached...