How does collision advoidance system activate the brakes

[5thranger]

If you think about it, being in the Ranger while it is being towed. The RV starts braking, the Ranger starts braking but there is a large motorhome just 6 ft away from your truck and as the brakes are applied ever stronger, the distance to the RV is still 6 ft. Then the Emergency Braking System lurches into panic. This is how it seems to me, but then I think nobody could be stupid enough to keep these systems active while being flat towed.

Oh yes there is.

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[got3fords]

Does anyone have the balls to actually drive towards a wall and test this out? If the brakes actually activate, would it stop in time to prevent contact? $20 for volunteer...

My coworker was being an ass one day when I was trying to park. He just stood there in my way, so I just kept going, got right up to him and the avoidance took over and stopped.

 

[Caseyjay]

Note: I do not Flat Tow nor do I have an in-depth knowledge of the Stay N Play (Demco) unit

Ok I see what is happening, now that I know you are Flat Towing.

Here is the operation of the system and why you are getting a hard braking action on the truck to match the motor home, now I am not exactly clear on how your added system operates (brake control) but it appears to match the motor home.
If you brake hard on the motor home, it's telling the truck to brake hard.

When the truck brakes hard, it's not running so no (Brake Booster Vacuum), and the ABS Module sees this and commands the HCU & Pump On, to obtain the braking action needed.

But to confirm here, the Stay n Play unit - has its own pump to provide booster vacuum, Correct?

If YES:
You may try Fuse 82 - Feeds the Pump, note fuse 82 is on the bottom side of the fuse box, kind of a pain to get access to it.
I believe there was a post or video on how to get access
The reason being if you depower the pump then you will eventually deplete proper normal braking action without an alternate pump.

Ref: This thread on a similar issue, poster mentions a revised tube on the brake booster

P103C and no brake boost in reverse? | 2019+ Ford Ranger and Raptor Forum (5th Generation) - Ranger5G.com

Yes the Stay-in-Play has n air pump which pushes a piston to retract the pedal. The inflow of the air pump goes to the brake booster to supply vacuum needed far easy braking. I am willing to try the fuse 82 fix, but your warning about deplete normal brake action has me worries. No you mean over a few hours or many days if fuse is removed long term? Also RangerBills video link has my own comments in them as I have tried to fix this over the years.

 

[Awg9Tech]

Does anyone have the balls to actually drive towards a wall and test this out? If the brakes actually activate, would it stop in time to prevent contact? $20 for volunteer...

I’ll take that $20. But I won’t be using a wall.

I was thinking about trying it out with a wide roll of tissue paper.

 

[DeerSlayer]

I've come up vehicles and pulled out to pass while the vehicle collision warning has come on while at a high rate of speed. No auto braking was intiated or I would have died. LOL!

 

[airline tech]

Yes the Stay-in-Play has n air pump which pushes a piston to retract the pedal. The inflow of the air pump goes to the brake booster to supply vacuum needed far easy braking. I am willing to try the fuse 82 fix, but your warning about deplete normal brake action has me worries. No you mean over a few hours or many days if fuse is removed long term? Also RangerBills video link has my own comments in them as I have tried to fix this over the years.

Meaning that after a few brake pedal presses the vacuum is depleted without the engine running, I was thinking that if the Stay n Play did not provide a way to replenish that vacuum the trucks ABS module would always have to replenish it.

I understand it now - the Stay n Play does and the truck is only reacting to a hard braking event, the Stay n Play is not providing enough vacuum to satisfy the truck ( programed) minimum pressure, that’s why the pump kicks on - only for a hard braking event.

If you pull the fuse - it should operate as an even braking action to match the motor home without the extra bump from the ABS Motor Pump that is causing the dip in the truck. The truck will still stop, just not as quick.

 

[Blue Streak]

Does anyone have the balls to actually drive towards a wall and test this out? If the brakes actually activate, would it stop in time to prevent contact? $20 for volunteer...

I will do it for free with your truck.?‍?

 

[Beach]

The first week I owned my Ranger a woman in front of me stopped suddenly as I was moving to the right lane with my head turned to the right to look for oncoming traffic. My truck stopped on a dime by itself and the crash avoidance indicator lit up and gave off a loud beep.

Good to know. Wish the Jeep that crashed into my rear on the highway had that, tech bro’s not paying attention almost killed a few of us

 

[Cabose-1]

My coworker was being an ass one day when I was trying to park. He just stood there in my way, so I just kept going, got right up to him and the avoidance took over and stopped.

What model trim level?? Because my ranger does not srop for s#$% unless i hit the brakes

2022 xlt fx2 no adaptive cruise

 

[Caseyjay]

Meaning that after a few brake pedal presses the vacuum is depleted without the engine running, I was thinking that if the Stay n Play did not provide a way to replenish that vacuum the trucks ABS module would always have to replenish it.

I understand it now - the Stay n Play does and the truck is only reacting to a hard braking event, the Stay n Play is not providing enough vacuum to satisfy the truck ( programed) minimum pressure, that’s why the pump kicks on - only for a hard braking event.

If you pull the fuse - it should operate as an even braking action to match the motor home without the extra bump from the ABS Motor Pump that is causing the dip in the truck. The truck will still stop, just not as quick.

I have pulled fuse 82 and drove my truck. Lots of error messages and warnings about automatic braking systems not working and such, but drove and braked ok. It went into flat tow mode without problem as well. No codes except P2610 which is about engine shut off timing. Maybe was set during the fuse removal. If this fixes the brake pedal slap, then I will probably try to install a simple SPST heavy duty switch to enable the circuit. I would leave it engaged unless towing. Will report on test in the next few days.

 

[got3fords]

What model trim level?? Because my ranger does not srop for s#$% unless i hit the brakes

2022 xlt fx2 no adaptive cruise

XLT 301A

 

[Msfitoy]

I will do it for free with your truck.?‍?

Dude you're crazier than me...my truck doesn't have crash bars, has spacers and brake pads with over 120k miles... ?

 

[airline tech]

What model trim level?? Because my ranger does not srop for s#$% unless i hit the brakes

2022 xlt fx2 no adaptive cruise

All Rangers should have - Pre-Collision Assist with AEB as standard equipment, the Adaptive Cruise was an (Option)
This using the 2021 options brochures - I would suspect the 22 to be the same, unless the shortages affected that.

 

[Caseyjay]

I have pulled fuse 82 (ABS) connecting the Ranger to my RV in flat tow mode and did stopping tests. Each time the rig stopped fine WITHOUT a brake clunk. I also did a video of the pedal as I braked and it showed smooth pedal motion without pedal slap as before. Therefore, I conclude that original brake surge complaint was caused by the automatic braking system, which remained active during towing, activating the brakes inappropriately. I will now get a high current switch like a battery disconnect and put in line with the ABS B+ line. I plan to disable the ABS for flat towing but otherwise leave on as normal. With it disconnected, I received lots of error messages and warnings about automatic braking systems not working, but also noted the Parking Brake light was lit (but not set) as well as no cruise control. However, it drove fine anyway. Thanks to all who helped. Special thanks to airline tech for technical advice

 

[buzzleo]

Ok, if I could pull a fuse for that system, I could test to see if that stops the pedal slam. I would not think that the ABS system is necessary to braking the Ranger while it is being towed

I set up a bunch of cardboard boxes and drove towards them. Didn't activate......I think u need to be going a certain speed. I didn't look that up at the time, got tired of fooling with it! It did save me once on the atl bypass during a sudden stoppage!

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