2021 6.6 Duramax service DEF system and service power steering warnings

[jasonhooker3]

I purchased a used 2021 Silverado 2500HD Z71 6.6 Duramax w/ 40k miles, 5 weeks ago from Penske GMC.

 

Two weeks ago I received a "Service Safety Restraint System" light. Took it to dealer who said I am 2 days past the 30 day warranty period. They said it was the front passenger seat haptic airbag sensor. They are checking to see if extended warranty will cover that.

 

Yesterday I received two warnings,

 

1. Service Power Steering Drive With Care, but Power steering feels a little over assisted, power steering fluid is full.

 

2. Service DEF System See Owner's Manual, I added DEF 3 days ago and truck has over half tank. 98 miles until 65 mph max.

 

This is my first diesel, any help or ideas will be appreciated. I understand every dealer trade-in was more than likely traded in for a reason, just hoping I didn't make the mistake of buying somebody else' lemon. Truck is unbelievably clean inside and out. 

 

 

 

 

Edited January 13, 2025 by jasonhooker3
power steering feels over assisted

[GMCustomerService]

1 hour ago, jasonhooker3 said:

I purchased a used 2021 Silverado 2500HD Z71 6.6 Duramax w/ 40k miles, 5 weeks ago from Penske GMC.

 

Two weeks ago I received a "Service Safety Restraint System" light. Took it to dealer who said I am 2 days past the 30 day warranty period. They said it was the front passenger seat haptic airbag sensor. They are checking to see if extended warranty will cover that.

 

Yesterday I received two warnings,

 

1. Service Power Steering Drive With Care, but Power steering feels fine, power steering fluid is full.

 

2. Service DEF System See Owner's Manual, I added DEF 3 days ago and truck has over half tank. 98 miles until 65 mph max.

 

This is my first diesel, any help or ideas will be appreciated. I understand every dealer trade-in was more than likely traded in for a reason, just hoping I didn't make the mistake of buying somebody else' lemon. Truck is unbelievably clean inside and out. 

 

 

 

 

Our team regrets to hear of this concern with your Silverado and understand how an unexpected occurrence can be worrisome. We would like to take this opportunity to learn more and assist where we can. When you have a moment, please send us an email to [email protected]. Be sure to include your Username and Forum name in the subject line with additional details. We look forward to hearing from you. 

[jasonhooker3]

Email sent

[jasonhooker3]

When the Service DEF system warning first came on, the DEF was at 1/2 tank. I filled it all the way up and warning light went away shortly after. Weird thing is the Service Power Steering warning went away at the same time and the power steering feels perfectly normal now??? When the warning light was on the power steering was very sensitive (overly assisted). The CEL remained on for 3-4 key cycles, and is now off. 

[jasonhooker3]

Dealer looked at truck and said they found a bad ground wire. Ground wire was replaced, ran great for a few weeks until service def system and service power steering lights came on again, and battery was completely dead the following morning.... Jumped truck, and after 5-6 key cycles, CEL went away. This is the 3rd or 4th time, the service DEF and service power steering lights have come on, followed by a dead battery in the morning. Once I get truck jumped, and after 5-6 key cycles, lights go away and battery is fine for a couple weeks. Timing of this problem seems to be consistent with regen periods???