Undocumented Cruise Control "Feature" ?

[jimjohnmarks]

Did a road trip in the '14 2.0T R-spec this past Thanksgiving week from Houston to Phoenix and back.

I-10 West of San Antonio all the way to the outskirts of El Paso is 80m/h speed limit.

Day to day driving in Houston, I often set the cruise control around 30-35 because many of our commuter streets have timed traffic lights and if you know the speed limit you can catch every light green without touching the brakes or shifting. So, by the time I get to the highway and nudge the cruise setting up higher and higher, I've long since set it somewhere quite low.

Twice on this trip I had occasion to pull off the highway, fill up with gas, and then drive straight back onto this 80m/h stretch of road. So the first number I tried to set the cruise control to was 79. The "cruise" light came on when I engaged the system, but when I clicked to set the speed, nothing happened and the "set" light did not come on. Slowing down to 65 didn't help. Turning the car completely off and re-firing didn't help. I was unable to set a speed until we'd made a stop of some time (for a meal, say) after which it would work again.

Is there a "feature" that doesn't let you set the cruise control at "illegal" speeds as the initial setting point? I don't see anything in the books on this, but I've had no other problems with the cruise control other than these two occasions doing something very unusual (AND LEGAL).

 

[amartz]

Mine will hold 79 quite nicely, thank you...

(It'll hold more than that, also!!))

 

[jimjohnmarks]

Mine will hold 79 quite nicely, thank you...

(It'll hold more than that, also!!))

Yes, so will mine. I've had it there many times. This was _specific_ to not setting it until after those speeds were reached. This trip was now pushing six months ago and I've had no failures since, and only the two in question at all.

Typically I set cruise at a street level speed and then bump it up to highway speeds later, but in rural west Texas that's not really an option and so it was start the car, drive up the ramp, get to the speed limit and set it... except it wouldn't set. And even with a complete re-start of the car wouldn't set for at least half an hour.

But the question isn't whether it will or won't set at such speeds. Only whether it is intended not to set directly to those speeds.

 

[jimjohnmarks]

Speed seems to have nothing to do with the issue.

In the 13 months since my original post this problem has occurred rarely, sporadically and randomly at all kinds of different speeds.

Since it doesn't pose any kind of safety risk, I just ignore it and hope it never happens again on a 1100 mile trip.

 

[guybo]

I set mine at 85 with no problem. I use my cruise at lower speeds a lot too, but I've never had problems setting it or using the cruise control knob to bump up the speed or re-set from a slower to a faster speed.

 

[jimjohnmarks]

I set mine at 85 with no problem. I use my cruise at lower speeds a lot too, but I've never had problems setting it or using the cruise control knob to bump up the speed or re-set from a slower to a faster speed.

I often do, too.

But I have found that (and I repeated this again this past November, the post is now 14 months old) if I start the car, and proceed directly from 0-80 (which you need to do to safely merge into traffic on I-10 west of San Antonio if you stopped to fuel up) and don't turn on the cruise control or set it until I get to 80, it will from time to time refuse to set.

Whereas if I first set it at 35 while making my way through timed traffic lights to get on the highway in Houston and then ramp it to some "much higher" number, it is just fine.

But there does seem to be something about going directly to atypically high (and on that stretch of I-10 completely legal) speeds before turning the system on or engaging which seems to give the computer pause.

Only annoying if it means doing the next stretch of 300 miles at 80mph without cruise control.

 

[Red Raspberry]

The problem is the brake light switch. If you cannot get the CC to set then give the brakes a quick jab. It should work then.

 

[jimjohnmarks]

The problem is the brake light switch. If you cannot get the CC to set then give the brakes a quick jab. It should work then.

It happens pretty rarely. I'll give that a shot next time it comes up, but I think I've tried everything including turning the car off (at 80m/h!) and back on again.

Is the real solution to have the switch replaced? The car is still under warranty.

 

[Red Raspberry]

There are two switches on the brake pedal. Not sure which one it is that is the problem. Perhaps some contact cleaner or WD 40 on the switch and then exorcise it?