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2008 DTS Performance
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3 Posts
Discussion Starter #1
I have noticed a problem recently with my 2008 DTS. I have a 30 mile commute to work (all highway driving), so I use cruise control extensively. I have noticed recently that when I am on a gentle downhill coast, the cruise control disengages.

It seems to happen in the same spot on my commute every day, so I have been watching as I approach that part of the road. I see that on the slight downhill section the speedometer will fluctuate wildly for about 1/2 second. Sometimes the speed displayed is 20 mph slower than I am travelling, and I am guessing that is why the cruise control disengages. I have seen on other vehicles that cruise control will typically disengage if the speed drops 10 mph below set speed and the engine still cannot keep up. Occasionally, I will notice that the engine revs quickly (causing the car to lunge forward briefly) just before the cruise control disengages.

Any ideas what is causing this? It used to occur very infrequently, but now it happens almost every day.
 

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2011 DTS Platinum
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4,633 Posts
Check the connection on the Vehicle Speed Sensor on the transmission...
I think it is a green wire...
 

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2008 DTS Performance
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3 Posts
Discussion Starter #3
I thought about that, but why would it only be an issue when coasting downhill? Speedometer doesn't have a problem any other time.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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68,531 Posts
In some of these cars if you even breathe on the brake pedal, cruise drops out. The switch is at the top of the pedal arm.
 

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2011 cadillac dts
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556 Posts
My going down hill it will speed up

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In the northeast there are alot up and downhills on our roads
 

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Registered
2008 DTS Performance
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3 Posts
Discussion Starter #6
Check the connection on the Vehicle Speed Sensor on the transmission...
I think it is a green wire...
I replaced the speed sensor since it was only $15 and checked all the connections. It seems to have fixed the problem although it was somewhat difficult to get to the speed sensor. It's a good thing I am 6'5" and have long arms so that I could reach the sensor by removing the passenger front wheel. Thanks for the help Superjim!
 

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Registered
2011 DTS Platinum
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4,633 Posts
I replaced the speed sensor since it was only $15 and checked all the connections. It seems to have fixed the problem although it was somewhat difficult to get to the speed sensor. It's a good thing I am 6'5" and have long arms so that I could reach the sensor by removing the passenger front wheel. Thanks for the help Superjim!
Always glad to be of help...:)
 
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