Non responsive Cruise Control

[Jay737]

Hi everybody
I have a Ford Transit Custom 2017 Manual, Crew Cab (basically Tourneo).
This van had a lot of issues over the last 5 years, but it was always something that my local garage managed to repair.
However, one persistent problem that nobody can answer is the non-responsive cruise control.
The symptoms are similar (but somehow different) to what other people reported here.

1. I'm able to turn it on (stand-by mode) and set the speed whilst moving over 20mph.
2. The CC will take over and cruise as normal ON SECOND AND THIRD GEAR ONLY.
3. In 4th, 5th, and 6th gear, though the set speed is being displayed (not crossed) on the dash, but THERE IS NO POWER BEING APPLIED by the CC. It appears to be active, but it's actually doing nothing, and the van just progressively slows down.
4. Pressing down on the brake or clutch pedals will effectively disengage the CC as expected.
5. The "Shift Guide" that advises you when to change gears disappeared a few months back, but occasionally shows up.

One thing I need to mention is that I fitted BFG All-Terrain tyres, but this was done when I first got the van. I think the CC was working fine with these tyres before (I can't remember to be honest). These tyres are about 10% bigger than the originals.

Any thoughts?

Thank you, gang.
Jay

[metalworker0]

if tyres are bigger or smaller, this make a difference, if this is not altered in the BCM ... which i believe you can do in forscan with the extended licence version .. how it makes a difference i'm not sure, but your speedo will be reading high or low .

all the best.mark

[Jay737]

if tyres are bigger or smaller, this make a difference, if this is not altered in the BCM ... which i believe you can do in forscan with the extended licence version .. how it makes a difference i'm not sure, but your speedo will be reading high or low .

all the best.mark

Thank you for your response Mark.
The speedo is about 10% off, since I fitted the new wheels, so I kinda got used to it (doing 27mph in a 30 zone and so on), but the thing is.. The van doesn't know how fast it's really going.
I mean, no matter how many times the wheel goes around, all modules receive the same data, don't they? There is no GPS-reliant system, so the actual speed should be irrelevant in this case.
Also, I did have a go at Forscan, tried to correct the wheel circumference, and it made no difference though.

Thanks
Jay

[metalworker0]

in the software .. so i read .. there is a correlation between RPM and wheel speed.

so the tyre size does have to be reset.

and suggest you put this into google .. and spend a few hours looking for solutions .. as ive spent 30 mins.

google search :

cruise control only in 1st 2nd 3rd ford

ignore the fact that it's a transit ,,. just look at all ford answers... as there are plenty of people with this problem, there are not any answers for transits with solutions so you'll be looking at fiestas mondeos , galaxy , focus , fusion, all of them in the time period your van was built . look more into answers for Ranger and F150


all the best.mark

[Jay737]

I can't believe it has come to this.. Thank you for your input, Mark.
But why, for the love of van, do we need a forum to find answers to issues created by the "creators"?
I've been to the Ford dealer a couple of times regarding this particular problem, and they just "don't know"..?
This is so frustrating....

[Jay737]

BTW, back to my previous theory, "correlation between RPM and wheel speed" should be constant no matter the wheel diameter. It's basically RPM of the crankshaft vs RPM of the wheel.
The wheel diameter is not relevant. Is it?

[metalworker0]

The wheels are a different circumference, so the making an error on with abs wheel sensors, system knows the diameter of the wheels and what rpm it should be doing for a given speed, you now have lower RPM for all speeds in all gears..
mind boggling . the system dont know or car what tyres are fitted unless one or two are different..... may be you are right .,.I have to sleep on it

Anyway do you have other features like lane assist . this im told cancels Cruz control if it detects no driver input to the steering wheel, which i suppose would happen at over 40mph .. as you are then almost certainly on a strait road .. is there is a sensitivity setting .. or time out setting ? does cruise control only work on strait roads .. are you expecting it to work on bendy one .. i don't know, never wanted or needed this feature myself .. im a fan of KISS - keep it simple stupid

maybe it needs a software update .. that wasn't done ?

all the best.mark

[metalworker0]

you are right

system don't know the actual; speed you are going .

so look at other things .. other than the tyres .. cancel tyres as cause .

if it has GPS ... well that changes things

all the best.mark