Speedo Correction option (1 Viewer)

[linuxgod]

Curiously watching this thread. With 35s, the offset is more than I like. I find myself driving faster, but I'll likely adjust in due time. Still interested in a possible fix, and I don't mind cutting and splicing as I trust my wiring work. Some of these PnP harnesses may invite some of their own vulnerabilities.

Part of the reason is that LX has other systems reliant on CANBUS speed, namely the AHC ECU. It should be lowering the suspension for freeway speeds at ~62mph, but it's currently happening closer to 70mph. As I rely on this behavior when towing, for the side effect of dynamically increasing weight distribution hitch tension at higher speeds for more stability. I've had to adjust my hitch head for more static tension.

I don't think this device will resolve the AHC speed-related issues but I'm not 100% sure. I also don't think it'll correct for any other systems (LC or LX) which rely on the vehicle speed for the same reason. Here's what I see for the LC...

Wires in question on the LC are violet and black and are pins A25/A26 in the EWD going into the Combination Meter Assembly, according to the PDF I linked and to the EWD. These same violet/black wires exist on the 2013 LX though they are pins A36/A35 respectively. (Note I assume this would be the same for all 2008-2015 but would need to browse all the diagrams to confirm).

The CAN-H/CAN-L wires track back to a junction which connects the network ECU, the main body ECU, and the ECM. From what I can tell this is intercepting the CAN signal and re-writing it before it goes to the meter. Unless the meter is sending the signal out to AHC, or unless this is generating a CAN message and sending it backwards up the chain to the network ECU, it's only being used to change the display.

Of note the Suspension Control ECU is separate from the Skid Control ECU on the LX. I suspect for AHC you need to "trick" the Suspension Control ECU, though I'd agree that if all the other ECUs are using their speed readings from the Skid Control ECU then you could probablyk achieve what you want by adjusting the input signal at that source.

From the PDF:

2013 Toyota LC:

2013 LX 570:

 

[Ferd]

From a different thread discussing suspension, I saw the Superior Engineering kits come with a CANbus speedo correction adapter. It looks like this is produced by Marks 4WD out of Australia and sells for 313 AUD (about $220), plus shipping.

Speedo Corrector - Toyota LandCruiser 70 Series | Marks 4WD

Our Marks4wd SPEEDO CORRECTOR allows you to adjust the TOYOTA LANDCRUISER VDJ70, VDJL70 & GDJL series speedo to compensate for tyre size and/or differential ratio changes.

www.marks4wd.com

I dug a bit and found these installation instructions. Looks like the hardest part is disassembling the dash to get to the connector:

https://cdn.shopify.com/s/files/1/0309/4370/7180/files/mfk1050-1.pdf?v=1603926303

FYI it looks like there's a German company which also manufactures a similar calibration kit for the 200, though I don't see any installation instructions on it. It's entirely possible the Marks kit is this plus a wiring harness and instructions.

Speedometer calibration

Control unit for calibrating the speed indicator in the speedometer

www.wenning.de

With my truck on 34s my speedometer reads about 5% low, so this is tempting to try. It's easy to adjust so if you go up/down in tire sizes you can flip a few switches to adjust the correction amount.

This is just a pre programmed Canny7 from canny logic that sells for ~ $50 US.

 

[linuxgod]

This is just a pre programmed Canny7 from canny logic that sells for ~ $50 US.

Well, the programming is the difficult part for most people. It may use the canny7 as it's method for communications, that I can't say, but the output side is different (toggle switches vs wires). In addition to the the logic portion, which for most people who don't know how to program the CAN communications is worth an extra $150 as it's actually programmed to *do* something, it's a tested product vs something you might DIY. Maybe that doesn't matter to everyone but if I'm playing with something that can send/modify CANbus data I'd like to know it's had at least a minimal amount of testing.

That said if someone wants to try to program a unique speed correction (instead of 2% adjustment increments) and is willing to spend some time with their development kit this could be a way to do so.

 

[BlackMammoth]

Well, the programming is the difficult part for most people.

I sell software for a living. You would be amazed how many people don't understand that!

 

[linuxgod]

I sell software for a living. You would be amazed how many people don't understand that!

I write software. (Or at least I used to). As they say the first 80% of the functionality is easy. It’s the last 20% (debugging, fine tuning, etc) that takes 80% of the time though.

 

[Ferd]

I write software. (Or at least I used to). As they say the first 80% of the functionality is easy. It’s the last 20% (debugging, fine tuning, etc) that takes 80% of the time though.

Guys have you seen how this thing is programmed. Go to the website and have a look, my dog could program one of these. there are also stacks of examples on the site. It's not programmed using C , its functional block drag and drop. super easy.
Just lookup the can packets that are sent to the speedo and those are the ones that need the payload corrected the dip switches are read in via the 8 data lines and used to interpret the division. yo can even load can bus sniffer firmware onto it and watch the packets to work out which ones are for the speedo.
Sure go and buy one and fit it if you like , but I assumed by the discussion that you guys wanted to make something rather than buy it.
Cheers.

 

[Ferd]

Guys have you seen how this thing is programmed. Go to the website and have a look, my dog could program one of these. there are also stacks of examples on the site. It's not programmed using C , its functional block drag and drop. super easy.
Just lookup the can packets that are sent to the speedo and those are the ones that need the payload corrected the dip switches are read in via the 8 data lines and used to interpret the division. yo can even load can bus sniffer firmware onto it and watch the packets to work out which ones are for the speedo.
Sure go and buy one and fit it if you like , but I assumed by the discussion that you guys wanted to make something rather than buy it.
Cheers.

The canny duo that they used has 2 can busses on it when you cut the can wires at the speedo you are isolating the speedo from the original can bus, the first can bus on the canny then connects to the main can bus in listen only mode, when it picks up a can packet addressed to the speedo it then creates a new can packet with the altered/corrected data that is generated using a multiplier selected on the dip switch. the second can bus on the canny is connected to the other side of the cut being the speedo to create the second isolated can bus with only the speedo as the slave. therefore in this situation you can do no wrong (assuming basic intelligence). there is a great video on youtube where the guy on Goat Rope Garage used one on a buick.
I am using one of these to engage my ARB air lockers at the correct speed and load via the Android Torque app on my radio screen instead of going out and buying an ARB Linx unit.

 

[Moby]

I sell software for a living. You would be amazed how many people don't understand that!

I write software for a living (Partner Director of Software Engineering, Microsoft, Cloud+AI). You'd be amazed how many "programmers" don't understand that

It's easy to write code. It's damn hard to make code really, really solid. Anyone that disagrees with that, well, good luck

 

[Ferd]

I write software for a living (Partner Director of Software Engineering, Microsoft, Cloud+AI). You'd be amazed how many "programmers" don't understand that

It's easy to write code. It's damn hard to make code really, really solid. Anyone that disagrees with that, well, good luck

Should be a breeze then.....

 

[cubaniche]

Resurrecting this thread to see if anyone has successfully tried this on the LX. Only interested purely in speedo correction. I followed another guide here on mud for my GX470 using a speedohealer device, found here:

Speedo Correction option

From a different thread discussing suspension, I saw the Superior Engineering kits come with a CANbus speedo correction adapter. It looks like this is produced by Marks 4WD out of Australia and sells for 313 AUD (about $220), plus shipping. https://www.marks4wd.com/mfk1050-1.html I dug a bit...

forum.ih8mud.com

I'm wondering if the same principle would apply here using the info linuxgod provided in post 21 of this thread? Basically, just tap into the two wires for the LX (can hi/lo) using this other canbus device this thread referenced in the opening post. I have zero qualms of splicing wires. It seems this thread died because everyone was more concerned with correcting the overall signal so that all control modules were on the same page as far as speed info is concerned. However, I just want the speedo to read right and don't care about the rest.

Any input would be welcomed.

 

[ttrmike]

Resurrecting this thread to see if anyone has successfully tried this on the LX. Only interested purely in speedo correction. I followed another guide here on mud for my GX470 using a speedohealer device, found here:

Speedo Correction option

From a different thread discussing suspension, I saw the Superior Engineering kits come with a CANbus speedo correction adapter. It looks like this is produced by Marks 4WD out of Australia and sells for 313 AUD (about $220), plus shipping. https://www.marks4wd.com/mfk1050-1.html I dug a bit...

forum.ih8mud.com

I'm wondering if the same principle would apply here using the info linuxgod provided in post 21 of this thread? Basically, just tap into the two wires for the LX (can hi/lo) using this other canbus device this thread referenced in the opening post. I have zero qualms of splicing wires. It seems this thread died because everyone was more concerned with correcting the overall signal so that all control modules were on the same page as far as speed info is concerned. However, I just want the speedo to read right and don't care about the rest.

Any input would be welcomed.

This worked for me: What have you done to your 200 Series this week? - https://forum.ih8mud.com/threads/what-have-you-done-to-your-200-series-this-week.818471/post-12947985

I’ve since updated the calibration a couple times as I’ve changed tire size. I set mine for the odometer to read accurately, which puts the speedo about 2mph high (like oem).

 

[cubaniche]

This worked for me: What have you done to your 200 Series this week? - https://forum.ih8mud.com/threads/what-have-you-done-to-your-200-series-this-week.818471/post-12947985

I’ve since updated the calibration a couple times as I’ve changed tire size. I set mine for the odometer to read accurately, which puts the speedo about 2mph high (like oem).

Awesome, thanks for the info. So, the same hypertech device should technically work on the LX using the pins outlined by linuxgod instead, is what I'm gathering. I'm running 35s and I'm likely going to regear as well, abs I just want the speedometer to tell me the correct speed. Not a fan of constantly going the math in my head, or using gps app on my phone etc.

 

[ttrmike]

Awesome, thanks for the info. So, the same hypertech device should technically work on the LX using the pins outlined by linuxgod instead, is what I'm gathering. I'm running 35s and I'm likely going to regear as well, abs I just want the speedometer to tell me the correct speed. Not a fan of constantly going the math in my head, or using gps app on my phone etc.

I just cross referenced what pins the hyper tech was intercepting on the tundra and transferee those to the LC pin out. Numbers were different between platforms, but the wires were the same function. I’m sure the LX pin out is similar.

 

[cubaniche]

I just cross referenced what pins the hyper tech was intercepting on the tundra and transferee those to the LC pin out. Numbers were different between platforms, but the wires were the same function. I’m sure the LX pin out is similar.

Awesome, thanks for taking the time to share and reply. I'll be trying out.