PSA: 85 MPH speed limiter trigger

[mikemcclain]

This is more of a PSA in case it happens to someone else.

 

I had new struts installed in the front 2 years ago, no problems.  Last year, I switched out the rear air shocks with no issues.  Very intermittently, I'll get a "service suspension" alert on the driver display.  I don't notice a change in handling or ride so never paid much attention.

Last week, I was traveling back from Keystone, CO, and the "service suspension" message came on.  I cleared the message and continued on.  Once out of the mountains, I attempted to set the cruise control but it wouldn't work.  All other steering wheel controls worked including cruise on/off, it just wouldn't set a speed.  Next, I was attempting a pass and around 85 MPH, the truck stopped accelerating regardless of pedal position.  I thought my transmission was going out (204k miles) but kept driving because the family was asleep and no CEL.  Truck would accelerate fine from 50-80 but at 85 it would just stop.  Well, doing some googling led to a discussion about the "service suspension" error triggering a mild limp mode where speed is limited to 85.  Stopped for gas, restarted the engine, and no problems after that and no service suspension message again.

 

Hope this helps someone.

[AngelS]

Did you ever find out what the issue was? Was the struts after market? I'm experiencing the same exact issue with my 2019 Suburban

[Kdeich]

How did you reset the service suspension?? I have the same thing popping up and would really like it to stop. Thanks! 

[mikemcclain8]

I put new shocks on the rear again a few weeks ago (65k miles on them and getting rough) and noticed one of the electrical connections wasn't "clicked" in.  I had trouble getting the new one to click in also until I spray the rubber with lubricant and it slid right it.  Haven't had the issue since then.  Also, the message/limiter would reset with turning the car off/on again.

 

BTW, the struts were put in by a shop so I'm not sure if it was OEM or after-market.