Cadillac Owners Forum banner
  • Hey everyone! Enter your ride HERE to be a part of this month's Ride of the Month Challenge!

1 - 12 of 12 Posts

·
Registered
08 CTS4 DI Hot Lava Edition PDZ AWD FE2
Joined
·
402 Posts
Discussion Starter · #1 ·
The cruise on my car seems to react slowly when going up inclines and then when it does it seems to downshift and overshoot the cruise setting before settling back down. None of my other cars ever had this type of response, (or at least not as noticeable or abrupt), as my cadillac. Any others have this issue? Fixes?
 

·
Registered
2019 Cadillac XT5 Platinum 2020 XT4 Premium Luxury
Joined
·
66 Posts
Our 2009 CTS4 does the same thing. Frustrating - and hard to explain to the nice officer who stops you for speeding when he catches you going around an uphill corner as the car jumps 5 mph over the limit. :annoyed:
 

·
Registered
2011 CTS AWD 3.6
Joined
·
69 Posts
I haven't noticed any issues with mine. Generally cruise is set ~70 mph and holds fine on hills. Downhill there might be a 1 or 2 mph increase. My wife noted this weekend that the CTS was slower to return to set speed when pressing 'res' and dropping 5 or 10 mph due to traffic than her Honda. The downhill let it roll and slower resume is likely an attempt to improve gas mileage.

I've set cruise at lower speeds on other vehicles (40ish mph) and noticed surging on small rises as the system notes the rapid speed drop and overcompensates before kicking out again. Will try it in the cts.
 

·
Registered
2016 XTS Premium
Joined
·
1,819 Posts
Not noticed any errors in setting and keeping cruise control speeds in my 08. Of course when traveling up very steep inclines and may be prudent to go to manual shift mode and shift to a lower gear.
How steep are these inclines?
 

·
Registered
08 CTS4 DI Hot Lava Edition PDZ AWD FE2
Joined
·
402 Posts
Discussion Starter · #7 ·
I should mention that I really notice this issue mainly on suburban roads where the speed limit is 35 - 40mph - not so much on highways where the setting is 65-70mph
 

·
Registered
2016 XTS Premium
Joined
·
1,819 Posts
We'll dont forget that you are on the border line for use of the system. That may have an affect and if the speed limit is 35-40 and you're on a hill I would expect there might be some problems.
 

·
Registered
08 CTS4 DI Hot Lava Edition PDZ AWD FE2
Joined
·
402 Posts
Discussion Starter · #9 ·
The system kicks in at around 25mph so I don;t think a 35mph setting is that close to the border line and this is not something that is common on any other vehicles i have or do still own. Just seems as though the cadillac wants to minimize throttle adjustments. The "inclines" are not steep - for example the incline for a bridge going over the highway, etc.
 

·
Registered
2011 CTS AWD 3.6
Joined
·
69 Posts
Sounds like it is worth a friendly conversation with a service advisor. Perhaps there is a TSB, perhaps you have a bad sensor someplace. The dealer may also have a similar car (year / engine) you can drive to compare cruise operation.
 

·
Registered
08 CTS4 DI Hot Lava Edition PDZ AWD FE2
Joined
·
402 Posts
Discussion Starter · #11 ·
I found the information below on a jeep forum. Does anyone know if this could be the case in a gm vehicle?

OVERSHOOT/UNDERSHOOT
If the vehicle operator repeatedly presses and releases the SET button with their foot off of the accelerator (referred to as a “lift foot set”), the vehicle may accelerate and exceed the desired set speed by up to 5 mph (8 km/h). It may also decelerate to less than the desired set speed, before finally achieving the desired set speed.

The Speed Control System has an adaptive strategy that compensates for vehicle-to-vehicle variations in speed control cable lengths. When the speed control is set with the vehicle operators foot off of the accelerator pedal, the speed control thinks there is excessive speed control cable slack and adapts accordingly. If the “lift foot sets” are continually used, a speed control overshoot/undershoot condition will develop.

To “unlearn” the overshoot/undershoot condition, the vehicle operator has to press and release the set button while maintaining the desired set speed using the accelerator pedal (not decelerating or accelerating), and then turning the cruise control switch to the OFF position (or press the CANCEL button if equipped) after waiting 10 seconds. This procedure must be performed approximately 10–15 times to completely unlearn the overshoot/undershoot condition.
 

·
Registered
08 CTS4 DI Hot Lava Edition PDZ AWD FE2
Joined
·
402 Posts
Discussion Starter · #12 ·
Follow up - I tried the routine as stated in the jeep forum and it does seen to have improved the overshoot problem I was experiencing. Now the cruise control seems to stay in the -1/+2mph range.
 
1 - 12 of 12 Posts
Top