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I posted this in the 40 page thread but wanted to get a new look so I copied it here.  

 

I have a 2017 Denali 3500HD with "loose" steering.  I don't usually give my resume' but I think it is relative to this subject.  For 12 years I was a professional test driver at a major competitor to GM.  I worked in the suspension development group at a proving ground testing and tuning shocks, spring rates, stabilizer bars, tires, etc.  My job was to dial in just the right amount of comfort vs handling vs steering response and feel.  Why is this important?  Because I am 100% confident I know what is causing my "loose" steering.  The problem is the digital steering assist tuning.   Although there is a documented issue with some steering gear boxes,  the "loose" steering in my vehicle is not from any mechanical problems with the gear box.  Please understand that I did not say no one has a gear box problem.  I am simple saying that GM has more than 1 issue due to poor steering feel.  

 

The problem with my truck has nothing to do with anything being "loose".  Here is the proof.  At all speeds below 45 mph the steering feels fine.  At speeds above 75 mph the steering feels fine.  If something was loose or wrong with my gear box or other mechanical steering component the problem would not magically go away below 45 mph and above 75mph.  In fact, with almost any kind on mechanical "loose" steering component the problem would be perceived as worse with most increases in speed.  

 

For folks with "loose" steering try this.  Pick a long straight level road.  Drive straight at 40 mph with the steering wheel straight.  Concentrate on the amount of effort (torque) it takes to turn the wheel 1 degree, 2 degrees, 3 degrees etc up to 10 degrees.  These are small movements of the wheel but you feel immediate effort required to turn the wheel these small amounts at speeds below 45 mph.  At 1 and 2 degrees of steering wheel movement there is effort but little to no vehicle response or yaw.  This effort is a "feedback" (although artificial and in the suspension tuning world effort is not necessarily feedback but for the sack of keeping it simple let's just go with that) to the driver about what is happening to the steering system and vehicle.  Now try this same procedure at 45, 50, 55, 60, 65, 70, 75 mph. Does the effort required to move the steering wheel these small amounts start to increase at 74, 75, 76, 77 mph?  If so, you have a poorly tuned digital assist system.   In my vehicle the worst speeds are 60-70 mph.  At these speed the initial 0-5 degrees of steering wheel movement require almost zero effort.  The digital steering is "over boosting" the required assist needed.  At speeds above 75 mph, my vehicle "magically" fixes itself and the effort required to move the steering wheel increases dramatically.  

 

I have read through all 39 pages of posts.  Some folks have described the exact problem I have.  "Loose steering" between 45-75mph.  Another fact is many have complained that their steering is no better after GM replaced multiple steering components including the gear box.  GM needs to assign an engineer to retune the digital assist.  I volunteer to help.  I just need access to the ability to change the power steering assist levels through the digital steering.  So GM if your reading this just look me up and I will help.  

 

I hope this helps others to identify their real steering problems.  I also hope GM fixes this with a simply retune of the digital assist parameters.  

 

Mike P.

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So you want the effort to be the same at 45 as it is at 70? There should be more effort at higher speed when you get outside of normal lane change maneuvers because you should have to overcome the system if want to make more than 5 degrees of steering at 70mph. Maybe I'm mistaken what you looking for.

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The problem with my vehicle is it has nice effort all the way up to about 50 mph,  then the effort level drops at 55, then lower again at 60, then basically zero effort at 65 mph.   Steering effort tuning is highly personal with what folks want.  Some want it heavy, some want it light.  Per GM's marketing on the digital steering, GM wants to reduce the effort required to steer under certain conditions.  In this case it's clear GM wanted to reduce driver fatigue on long highway cruises.  My opinion (and other's who have complained) is GM went too far with the effort reduction at 60-74mph.  Above 75 mph GM engineers (in my opinion) correctly tuned it requiring much more steering effort.  

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I did contact PPEI to see if they offered a custom program for the module that controls the power steering digital system.  They said no.  I'm sure if many folks were asking for this custom feature PPEI or someone else would offer it.   

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