Emergency Brake Assist and Towing on Gravel

Do the prado's have trailer sway control? Yes, Gravel, sand and corrugations can play silly buggers with electronics which are ordinarily great things. We had a 105 series and standard operating procedure after a number of close calls on the sand was to pull the ABS fuse - it wasn't at all well calibrated.

Is "EBA" some kind of collision avoidance system? It detected the kangaroo and braked?

J&A&KK
Not sure if the same system as is used or called the same, but with earlier Corolla vehicles and most new vehicles they have a Brake Assist feature built into the actual vacuum booster valving. As you brake it initially appplies more boost than you need and give a more quick application of the vacuum boosted system.
Even so, the brakes lights would have been activated and the electric brakes on the caravan should have begun operation and kept it stable.
Maybe the controller is not solidy attached to the vehicle and flaps around when under the effects of corrugation and not able to sense the vehicle decelleration correctly OR the trailer brakes are set with insufficient initial braking. If the caravan braked all should keep in line to a reasonable extent.
The above is different to ABS operation, which as mentioned above may not work well in offroad conditions. Even then the trailer should begin to brake, is your manual override of the controller handy to reach? It is those instances when it comes in very uselful.

Yes scares the sh=it out of you it is Not ABS or stability control it is a whole different thing
Quote from Wikipedia
"Overview
Many drivers are not prepared for the relatively high efforts required for maximum braking, nor are they prepared for the "buzzing" feedback through the brake pedal during ABS operation. If an emergency develops, a slow reaction and less than maximum braking input could result in insufficient time or distance to stop before an accident occurs.

EBA is designed to detect such "panic stops" and apply maximum braking effort within milliseconds. It interprets braking behaviour by assessing the rate that the brake pedal is activated.

If the system identifies an emergency, it automatically initiates full braking more quickly than any driver can move his or her foot. Emergency stopping distances can be shortened, reducing the likelihood of accidents – especially the common "nose-to-tail" incident.

An electronic system designed to recognise emergency braking operation and automatically enhance braking effort improves vehicle and occupant safety, and can reduce stopping distances by up to 70 ft (21 m) at 125 mph (201 km/h)[2]

Brake Assist detects circumstances in which emergency braking is required by measuring the speed with which the brake pedal is depressed. Some systems additionally take into account the rapidity of which the accelerator pedal is released, pre-tensioning the brakes when a "panic release" of the accelerator pedal is noted. When panic braking is detected, the Brake Assist system automatically develops maximum brake boost in order to mitigate a driver's tendency to brake without enough force. In doing so, Brake Assist has been shown to reduce stopping distance by a significant margin (up to 20% in some studies)" end quote....

I had it on my Prado 2013 one mongrel thing .. if you hit the brakes a bit quick it thinks you are in a actual emergency and applies brute force , you nearly get seat belt burn
The 200 series is the same
I sold my prado and when back to the 100 series

I feel your pain John
cheers Bob
ps when it goes into this mode the brake lights flash to warn other drivers

New caravans have an anti sway in them (Al -KO ESC for example) and my vehicle (LR D4) has anti trailer sway. I have felt both come into play in some circumstances. I can switch off (and sometimes do) the caravan because on dirt roads or 4WD tracks, getting on funny angles causes the brakes to be applied.

Yes John, it is dwell time from accelerator to brake pedal , trying to slow that down in an odear moment is hard to do , most annoying brake aid , it would definitely be great in an emergency but a quick stab of the brake and it comes into action, is not
bob

All these things work really, really well on blacktop but once we enter the real world of corrugations and dirt the wheel turns. I wish I could turn abs off on dirt as it has caused me heartburn many times with both trucks, trailers and my road vehicle.

Your best friend is the trailer brake lever on your controller to keep you in reasonably straight line.

John,

Your story serves to remind all of us with more than a few years of "off the black top" towing experience of the odd oh sh*t moments we have. Whether it is a momentary lack of concentration, a mechanical failure or as in your case a roo wanting to race you to the ever after. We can all stuff things up on our own without a computer operated braking device buying into the argument. You have given me food for thought as I ponder my next new car which will inevitably have EBA on it. We have all heard of the ABS issues on corrugated roads but that can be disabled in most vehicles if you remember.
By the way I reckon you deserve a medal (in addition to a new pair of jocks) for being able to recover the situation. That was almost certainly due to your experience and instincts kicking in under stress. Thanks for the heads up.
Ken

would be interested to know if EBA works or not if you are a left foot braker.
not into towing but often use a dab of left foot to momentarily slow and straighten things out.
in this situation there is no dwell time as foot is on both brake and accelerator so am not sure if system would work or not .
cannot test it myself as fortunately my vehicle doesnt have such nicities/nasties.
cheers
Howard

Another good reason to not buy a Toyota if you cannot control your own braking and the car takes over - if there is an accident, who is at fault - the driver or Toyota.

Appreciate the comments from everyone.

Howard(ACT) suggested to try left foot braking to check if the EBA would activate.

So I tried that today on a number of occasions starting at 40 kph all the way to 100. At no time did the EBA activate. So a good suggestion Howard.

Now I have to train the brain to use the left foot for braking, even under “ instinctive emergency conditions”. Not sure how that will go. Most likely cause an accident whilst practising.

Cheers John