cruise control speed discrepancy

[xlfactor]

Greetings everyone,

This is my first post in here.

I'm a bit concerned about the cruise control on my car. Mine is the 2012 limited Explorer in Dubai, UAE, with adaptive cruise control.

Whenever I set the cruise, the outcome is always 2 or 3 km/hr short on the speedometer indicator gauge. For example, if I set the cruise to 120 km/hr, the final output is always 117 or 118 on the speedometer gauge, but the cruise control indicator shows 120. This happens with or without the adaptive cruise enabled.

Not sure if this is a normal tolerance limit with ford trucks as this is my first one. I'v never encountered the same on other make vehicles, as all other vehicles that I have driven with cruise control, the demanded speed always matched up spot on with the speedometer gauge.

 

[deerfarm]

My 2011 with adaptive has always seemed to be closer than that.

 

[xlfactor]

cruise control discrepancy

@deerfarm thank you for your response. On your truck, is ever spot on accurate? or is there always a slight marginal difference. Want to know whether this slight discrepancy is normal or is it something I need to get checked.

If it is normal then I would guess on my gauge the difference would be a bit more because over here we use KM/HR (not really sure though..just guessing).

 

[plumbago]

Either way you could check it against a measured distance with a GPS. GPS will easily read out mph, over a given distance...see where that fits between the speedo, digital read on cruise, and GPS read out.....You could also, over a measured distance, use a stop watch timed run, over say a mile at 60 mph.....and compare all the numbers just to see where your at.....On mine the GPS and cruise read very close, and the speedo usually indicates, as near as I can tell 1 to 2 miles slow..........best regards Plum

 

[peterk9]

Greetings everyone,

This is my first post in here.

I'm a bit concerned about the cruise control on my car. Mine is the 2012 limited Explorer in Dubai, UAE, with adaptive cruise control.

Whenever I set the cruise, the outcome is always 2 or 3 km/hr short on the speedometer indicator gauge. For example, if I set the cruise to 120 km/hr, the final output is always 117 or 118 on the speedometer gauge, but the cruise control indicator shows 120. This happens with or without the adaptive cruise enabled.

Not sure if this is a normal tolerance limit with ford trucks as this is my first one. I'v never encountered the same on other make vehicles, as all other vehicles that I have driven with cruise control, the demanded speed always matched up spot on with the speedometer gauge.

Welcome to the Forum xlfactor. :wavey:
This was a topic that was previously discussed as well. Mine is the same, so if I want the ACC set at 50, I wait until the speedo reads 52 or 53 and then set the ACC.
I personally don't think it is a big deal.
You can always bump your ACC up to 120 by using the steering wheel SET control. If you press it toward + it increases the speed 2 kmph, I believe.

Peter

 

[deerfarm]

@deerfarm thank you for your response. On your truck, is ever spot on accurate? or is there always a slight marginal difference. Want to know whether this slight discrepancy is normal or is it something I need to get checked.

If it is normal then I would guess on my gauge the difference would be a bit more because over here we use KM/HR (not really sure though..just guessing).

I would say that mine is about one mph lower than actual. I checked it once with a hand held gps.

 

[peterk9]

ACC and Speedo In Sync

After posting that my speedometer and the ACC set point were off a 2-3 kmph, I noticed today that they were right on. When the speedo hit 80 kmph I engaged the ACC and it also showed 80. Perhaps this is because I'm now running on the 17" Winter wheels instead of the OEM 20" wheels. I'll try to remember to watch this again when I put the 20's back on at the end of the month.

Peter

 

[xlfactor]

Thank you folks for all the useful feedback. I suppose this discrepancy is a normal tolerance limit, the way ford has designed this truck. In my opinion, I think 2 or 3 km/hr is a bit too much...but I somehow have a feeling that it is probably because the cruise control computer default calculating/processing units are set to MPH to a particular (+/-) tolerance range and when viewed in KM/HR, the range increases because of the conversion. @peterk9, please do update when u change back your wheels.
Best Regards
- xlFactor

 

[peterk9]

Thank you folks for all the useful feedback. I suppose this discrepancy is a normal tolerance limit, the way ford has designed this truck. In my opinion, I think 2 or 3 km/hr is a bit too much...but I somehow have a feeling that it is probably because the cruise control computer default calculating/processing units are set to MPH to a particular (+/-) tolerance range and when viewed in KM/HR, the range increases because of the conversion. @peterk9, please do update when u change back your wheels. Best Regards
- xlFactor

Oh great, something else to try and remember.
I was planning to do that and will mark it on my calendar.

Peter