Crawl Controll Hack?

[itr1275]

My understanding is that the crawl control feature on the Off-Road models controls the throttle and the brakes to emulate a crawler transfer case.

Since all of the 4wd 4runners have A-Trac, you could theoretically create your own crawl control by plugging into the ODBII connector and manipulating the throttle and brakes.

To take it a step further you can create your own MTS. Although the algorithms are probably pretty complex.

Will it work, has anyone done this?

 

[Mutant138]

My understanding is that the crawl control feature on the Off-Road models controls the throttle and the brakes to emulate a crawler transfer case.

Since all of the 4wd 4runners have A-Trac, you could theoretically create your own crawl control by plugging into the ODBII connector and manipulating the throttle and brakes.

To take it a step further you can create your own MTS. Although the algorithms are probably pretty complex.

Will it work, has anyone done this?

It controls throttle and pulses the abs to find traction. Not an expert but it seems like an extremely complicated hack and an absolute nightmare to figure out. As a car nut who has gone deep into many projects I can say trading your truck for one with crawl control would prob be the easier (possibly cheaper) route.

Prove me wrong my computer savvy friends.

 

[Swarty]

Not Quite

My understanding is that the crawl control feature on the Off-Road models controls the throttle and the brakes to emulate a crawler transfer case.

Not a crawler transfer case. It emulates low speed fully locked difs in a way.

Since all of the 4wd 4runners have A-Trac, you could theoretically create your own crawl control by plugging into the ODBII connector and manipulating the throttle and brakes.

To take it a step further you can create your own MTS. Although the algorithms are probably pretty complex.

Will it work, has anyone done this?

You could do this somewhat. I'm not sure how much if any ABS control you get through the OBDII but the Pedal Commander and its competitors works pretty much how you are thinking, reworking the throttle inputs albeit through the throttle by wire unit. MTS only functions at low speeds. You would have to look at the circuit diagram to see if MTS and crawl control wire directly to the ABS. I would think if this was all that easy an aftermarket controller would already be available from the same people making things like the power commander.

 

[Jetboy]

I've had some fairly complex discussions with an owner of a fairly well-known offroad shop that specializes mostly in Tacoma's. And we've discussed the possibility of hacking the ABS sensor signals to allow more complex things like skid steer. However I don't know that anyone has gotten far enough into it to do so. It is absolutely possible to do that. However it'll take a little bit more complex Electronics than a typical Speedo fix type device that modifies the output signal a small amount. In this case we need to show that the tire is over speed rather than under speed. And to do a correctly you need it to be done on an adjustable basis independently on each Channel with some type of control mechanism. I think a Raspberry Pi with the right programming is perfectly capable of doing it. But we need to write some code to make it work. And it would probably work best on a limited with a open Center differential. I don't remember if you can open the center differential on a limited in low range.

The biggest hurdle that you'll run into doing so is that the first part of the process is to trick the computer into thinking the two tires on one side are spinning freely. Doing that results in application of the brakes to that side of the vehicle. The problem occurs when one of the tires on the other side then also spins freely. In that case the vehicle will think that it also maybe needs to apply the brake Force to the driven side of the vehicle. And the result is likely to be applying brakes to both sides of one axle at the same time. And that will almost certainly result in a blown up differential or axle shafts. So the bypass computer you would design would need to take that into account and effectively manage all four channels of the ABS sensor signals.

After looking at what it would take to do something that's relatively simple compared to the complexity of what crawl control does, if you want crawl control you're better off to simply trade your 4Runner for one with crawl control. Or spend the money on front and rear locking differentials.

You could certainly trick a track to be a little bit more aggressive. However, I think there's a question of how far you really want to go with it. The drivetrain is only so strong. Too much and you're going to start breaking axle shafts or differentials.

 

[mo_mo]

My understanding is that the crawl control feature on the Off-Road models controls the throttle and the brakes to emulate a crawler transfer case.

Since all of the 4wd 4runners have A-Trac, you could theoretically create your own crawl control by plugging into the ODBII connector and manipulating the throttle and brakes.

To take it a step further you can create your own MTS. Although the algorithms are probably pretty complex.

Will it work, has anyone done this?

I’m not sure that you can send commands for throttle or brakes through the obd2 port. I do recall reading that someone ‘upgraded’ their sr5 to add crawl control but they basically took the 4wd control box and crawl control panels and rewired the system. Also, the trails came with a slightly higher current rating alternator than the sr5s, but that could have been for the locker actuator or maybe it was for the additional abs work.

As Jetboy mentioned, it would be cool to add the skid steer for tight turns like the land cruiser now has.