Persistent Electric Power Steering "Assist Reduced" Warning

LST3 · February 15, 2022

I am having an issue with me 2017 Silverado 1500 LTZ.

Each time I start the truck I get a "Steering Assistance Reduced Drive with Care" warning on the DIC. It goes away when you hit dismiss, but it comes on every cycle of the ignition. It currently has no lights on on the dash.

The backstory;

I was towing a large trailer on Thursday and got stuck in some slick snow (only maybe 8" deep, but very wet and it was a hill). I was already in 4 low at the time. It was stuck and I pulled it out. At some point while stuck, the service stabilitrac warning came up (the dash lights were already on because it was in 4 low, but now they stayed on even back in 2 hi). The traction control turned back on once driving, but the stabilitrac system stayed disabled. Once I drove a few miles I checked the codes with my scanner. No engine codes, but there were two codes present in the ABS module. One code was for the steering position sensor and the other code was a for a communication BUS being off/loss of connection. Clearing the codes turned all of the lights off on the dash and got rid of all of the warning messages EXCEPT the power steering message.

Rechecking the codes and my scanner tells me that there are no codes in any of the modules that it can connect to (ECM, ABS, SRS, and I believe that is all it connects to). Watching the live data output from the ABS module shows me the steering position sensor output. It appears to work fine and changes as the steering wheel is turned (appears smooth, sensor output doesn't jump around or anything).

I have driven the truck probably a dozen times since this happened and the power steering seems to work fine. It does not jerk the wheel and it feels completely normal. It still has no codes according to the scanner and no lights are on, only that single warning message. I have tried unhooking the battery twice. The first time I left it unhooked for several hours.

I am planning to check the dash grounds today as well as any other grounds that I can find. If no change, I will move to attempting to check the steering rack connectors as well.

Beyond those items I am stumped and not sure what to check next. I really don't want to take it to a dealer to have them scan it, but I know that may be the next option.

I have heard a few people saying their module needed reprogramming (and a recall, but only for 2014 models). I would at least feel more comfortable going to a dealer if I had a TSB number or something to reference.

EDIT: Cruise control also works fine.

Edited February 15, 2022 by LST3

swaukechon · February 17, 2022

I have the same truck and was having the same issues I tried having the power steering module reprogrammed and it worked until I put the truck in 4wd then lost power steering. Long story short I took it into the dealership and they said the rack needs to be replaced $2000 I hope you have better luck

LST3 · February 17, 2022

Interesting, what were your codes that caused it originally and what were the symptoms?

I ended up having a friend use his Snap-On scanner to clear the code. It worked fine and it immediately stopped the warning from coming up. I haven't driven it too many miles yet, but I have used 4wd and it all worked fine (even 4lo which is where the problem occurred originally). The warning stayed off.

Have you read through this TSB? I ended up finding it elsewhere. My truck falls right into the 2017-2018 model year date and the plant code given in the TSB. But if it was a more serious issue causing the warning originally, then yeah a reflash wouldn't fix it.

Knock on wood, it's been perfect since.

MC-10176334-9999.pdf