WARNING: Counterproductive "safety" features.

[Ron50]

Oh … I see now.

Does your Grenadier have autonomous emergency braking?

Haven't seen any reference to it but this incident suggests it could have.

My understanding of how stability control works is that it brakes individual wheels to straighten the car up; whereas autonomous emergency braking slams them all on at once.

There was no oncoming traffic or even nearby foliage for the camera/radar to detect to suggest an emergency and I had not applied any braking.

In the circumstances, with light throttle and a reasonably high gear, all the wheels would have been travelling at the same speed so you wouldn't expect ESC to be triggered either.

So I'm in the unfortunate position of not even being sure of the causal factors so that I can avoid them in future.

If the car doesn't have emergency autonomous braking maybe there was enough throttle on the skatey loose gravel surface to trigger the ESC to apply the brakes on all wheels simultaneously.

Up to the point of the incident the car had felt as if I was in complete and normal control - no warnings that I was pushing things.

 

[Michael H.]

Haven't seen any reference to it but this incident suggests it could have.

My understanding of how stability control works is that it brakes individual wheels to straighten the car up; whereas autonomous emergency braking slams them all on at once.

There was no oncoming traffic or even nearby foliage for the camera/radar to detect to suggest an emergency and I had not applied any braking.

In the circumstances, with light throttle and a reasonably high gear, all the wheels would have been travelling at the same speed so you wouldn't expect ESC to be triggered either.

So I'm in the unfortunate position of not even being sure of the causal factors so that I can avoid them in future.

If the car doesn't have emergency autonomous braking maybe there was enough throttle on the skatey loose gravel surface to trigger the ESC to apply the brakes on all wheels simultaneously.

Up to the point of the incident the car had felt as if I was in complete and normal control - no warnings that I was pushing things.

Mine definitely doesn’t have AEB, but I wasn’t sure if newer Aussie spec Grenadiers had it.

If you had it, you’d also have lane departure warning, intelligent speed assist and driver drowsiness detection.

 

[Ron50]

Well, bugger, page 114 of the paper manual says ESC off cancels at speeds above 15 mph/25 kph. My test drive just confirmed this.

 

[Shopkeep]

Maybe on dirt roads at speed you should have the centre diff locked and be in high, not sure if this alters or tweaks the ESC but might reduce excessive power transfer to any given wheel causing slip and reduce chance of ESC trying to intervene?

 

[Michael H.]

Well, bugger, page 114 of the paper manual says ESC off cancels at speeds above 15 mph/25 kph. My test drive just confirmed this.

Just to clarify … it says that you can’t turn ESC back on (if you’ve deactivated it with the ESC OFF button) at speeds above 15mph/25km/h.

And it's wrong by the way. You can turn it back on at any speed.

It’s been corrected in the electronic manual.

 

[chrsbe]

I had a very similar experience in my Suzuki Jimny which has a passenger detection via camera system. It was ether this system or dirt on the abs sensors that caused an emergency brake without reason. So i guess it is not a Grenadier problem. It is these systems that needed to be turned off on dirt tracks.
With my grenadier i experienced a lot of false esg interventions while driving through very very loose sand. Hitting esg off button helped and solved the problem.

 

[Ron50]

Just to clarify … it says that you can’t turn ESC back on (if you’ve deactivated it with the ESC OFF button) at speeds above 15mph/25km/h.

And it's wrong by the way. You can turn it back on at any speed.

It’s been corrected in the electronic manual

Maybe on dirt roads at speed you should have the centre diff locked and be in high, not sure if this alters or tweaks the ESC but might reduce excessive power transfer to any given wheel causing slip and reduce chance of ESC trying to intervene?

Worth a try. Thanks.

 

[Michael H.]

Maybe on dirt roads at speed you should have the centre diff locked and be in high, not sure if this alters or tweaks the ESC but might reduce excessive power transfer to any given wheel causing slip and reduce chance of ESC trying to intervene?

Locking the centre diff puts ESC into off-road mode, which desensitises it.

 

[Ron50]

Maybe on dirt roads at speed you should have the centre diff locked and be in high, not sure if this alters or tweaks the ESC but might reduce excessive power transfer to any given wheel causing slip and reduce chance of ESC trying to intervene?

Thanks again for your input, Shopkeep.

After my last test drive I found that my car behaves, in accordance with the manual, as follows:

Normal mode with ESC off button pressed holds until 78 kph then ESC becomes fully enabled.

Centre diff locked without ESC button pushed maintains ESC off road mode from low to very high speed.

Centre diff locked and ESC off button pressed holds from low speed to 78 kph and then transfers to ESC off road mode and will hold it to very high speed.

Panic braking on sealed surface seemed consistent with normal ABS operation - no detection of autonomous emergency braking.

 

[landmannnn]

Thanks for that: really good to know the ESC will stay off. I couldn't determine this from the owners manual.

Maybe I'll be able to gain some trust in my car down the track.

My mistake, it does turn off at 48mph or so.

 

[Ron50]

So off-road mode takes ESC to ESC off-road.

Could it have been the truck hitting the proper speed and turning off OFF-ROAD mode, then ESC off-road switched to full ESC? And that caused ann issue since you were on gravel maybe slipping in the corner?”

I'm liking your theory more and more, Phred, after finding the changeover speed of 48 mph/78 kph was probably the speed I got to accelerating up the slightly uphill straight.

 

[DaveB]

The quote was from an electronic version of the manual that I downloaded last year.

I just checked the paper version that I got with my car in July 2023, and I can’t find any reference to the speed at which ESC re-activates.

I think the electronic version was from UK spec vehicle, no idea what is different.

 

[Clark Kent]

It's a pity cars don’t have something like flight data recorders so we could analyse what happened.

Airbag Control Module.

Over Christmas my wife and I listened to a few true crime podcasts during a long road trip. One podcast was about a 62 year old blind man Ray Meadows and his trained guide dog Gerry. Ray and Gerry were both killed in June 2019 when they were struck by 22 year old Billy-Jo Salter driving a 2015 Corolla.
Billy-Jo maintained that Ray and Gerry were walking down the middle of the road. Through some clever reconstruction and investigative work the Victoria Police established that Ray and Gerry were on the shoulder of the road and Billy-Jo veered off the road and hit them.

A key part of establishing this was analysis of the data stored on the airbag control module which continuously records data like speed, brake pedal position, cruise control status and steering wheel angle. More info here.
The data revealed that in the 5 seconds leading up to impact and airbag activation the car was on cruise control and Billy-Jo did not turn the steering wheel to follow the curvature of the road where the accident occurred. The car travelled straight and departed the road and killed Ray and Gerry.

The podcast is here if interested. In December 2021 Billy-Jo was sentenced to 3 years and 9 months detention for dangerous driving causing death.

Extract from the podcast transcript:
Detective Acting Senior Sergeant Jenelle Hardiman:
What I proved using some computer programs and just a calculator and a pen and paper was that, to counteract the curvature of the road and the crossfall, a driver would need to input between nine and 12 degrees of steering to stay travelling straight.
So when we went back to that data, it showed that in the five seconds prior to impact, he never input more than three degrees.
And, in fact, my work with Toyota showed that up to three degrees is no steering. So the driver, being Billy-Jo, did not steer at all in the five seconds up to the crash.

 

[Michael H.]

Airbag Control Module.

Over Christmas my wife and I listened to a few true crime podcasts during a long road trip. One podcast was about a 62 year old blind man Ray Meadows and his trained guide dog Gerry. Ray and Gerry were both killed in June 2019 when they were struck by 22 year old Billy-Jo Salter driving a 2015 Corolla.
Billy-Jo maintained that Ray and Gerry were walking down the middle of the road. Through some clever reconstruction and investigative work the Victoria Police established that Ray and Gerry were on the shoulder of the road and Billy-Jo veered off the road and hit them.

A key part of establishing this was analysis of the data stored on the airbag control module which continuously records data like speed, brake pedal position, cruise control status and steering wheel angle. More info here.
The data revealed that in the 5 seconds leading up to impact and airbag activation the car was on cruise control and Billy-Jo did not turn the steering wheel to follow the curvature of the road where the accident occurred. The car travelled straight and departed the road and killed Ray and Gerry.

The podcast is here if interested. In December 2021 Billy-Jo was sentenced to 3 years and 9 months detention for dangerous driving causing death.

Extract from the podcast transcript:
Detective Acting Senior Sergeant Jenelle Hardiman:
What I proved using some computer programs and just a calculator and a pen and paper was that, to counteract the curvature of the road and the crossfall, a driver would need to input between nine and 12 degrees of steering to stay travelling straight.
So when we went back to that data, it showed that in the five seconds prior to impact, he never input more than three degrees.
And, in fact, my work with Toyota showed that up to three degrees is no steering. So the driver, being Billy-Jo, did not steer at all in the five seconds up to the crash.

That’s very interesting. I wonder how long the information stays in memory before being overwritten.

 

[Clark Kent]

That’s very interesting. I wonder how long the information stays in memory before being overwritten.

I suspect it's a short loop. The crash response.com website says 'The amount and type of data recorded in either a deployment or non-deployment event varies with the manufacturer and the model of the vehicle.'

 

[SQF1]

I conducted forensic fatal accident investigations in a former life, prior to retirement. CDR (Crash Data retrieval) is a common tool. The airbag module records EVERYTHING. The system has several layers. The airbag sensors work in miliseconds and normally run on a loop, if they detect a "wakeup" event (bump) it initiates the recording IIRC 500ms recording. In milliseconds the system determines if an airbag deployment is needed. If it turns out it was just a bump the system goes back to sleep and that info is recorded in the module for 20-25 key cycles and then written over. If airbags deploy the information is locked and will never be written over. The amount of information the Airbag module is processing in milliseconds is mind boggling. acceleration, throttle position, brake percentage, direction, yaw, tilt, position of seats in relation to airbags (closer to wheel airbag will deploy with less force), seatbelt connected or not. Depending on speed if seatbelt is showing connected the car may not fire airbag (this is why you never "trick" the car into thinking seatbelt is connected). If seatbelt is connected car may fire a pretensioner to draw you back into the seat before airbag goes off (why it is even worse to run belt behind seat and connect, pretentioner will throw seatback forward and you, without having seatbelt on, will be launched into the airbag before it fires, in turn when it fires you are thrown back.