SR01

The problem is either 1) a bad steering sensor and the systems software logic error or 2) a software systems logic error initiated by factory specified excessive amperage battery current draw, and an intentional logic flaw in the main computer. What are the facts and symptoms for each: 1) Bad steering sensor and logic error: The main steering wheel has a MEMs gyro sensor similar in design and construction to the airbag gyro sensors. The gyro sensors malfunctioned when temperature and humidity conditions breached a non hermetic seal in the sensor package causing a change in its output characteristics beyond calibration. Water vapor on the fingers of the MEMs to chip surface caused a stiction to movement. The change was temporary as it went back to normal over time as the humidity dropped and the transfer curve returned to normal following a consistent hysteresis curve. Small steering moves are falsely sensed as excessive moves demanding excessive current draw. If the conditions is periodic, and prevalent during season changes this could support the bad sensor. Excessive current draw is sensed by the main computer and under current logic the main computer shuts down critical systems during the drive. These systems include, power steering, power brakes, horn, diming of lights and ultimately a total power shutdown. After shutdown, OnStar is disabled. The original logic is to prevent driving a car when there is an unexplained excessive power draw as a safety feture. The problem is this is applied to a moving vehicle, in operation such as turn or a lane change. In addition, when a crash occurs, the horn, lights and OnStar is disabled. The problem starts early with soft failures and progresses to worse over time. Soft failures such as stabilization errors or ABS errors during changing lanes. Errors build and the body control module gets overwhelmed and eventually shuts down. You will get a raise and lower the driver's side window message which resets some of the errors. 2) Good steering sensor gyro, but a software systems logic error caused by excessive amperage battery current draw, and an intentional logic that is flawed. The problem (current draw) can be caused by a combination certain conditions: Some people report the problem during a turn at city speeds after driving a highway speeds. If one is using air conditioning, headlights are always on, ideling speed RPMs are near 500 rpms and one slows down during a turn at city speeds (even slower in the winter time with ice and snow) conditions become ripe for failure. The low idle rpm is insufficient to meet the amperage demand and the false systems logic shuts down power steering, and power breaks during the turn. Crazy logic used is one still has breaks, and steering, just not power assist. However, who can react to a turn when ABS kicks, raising speed, pumping brakes while excessive force is required simultaneously for steering and brakes to prevent crossing into the next lane which can have a vehicle in it or even during a 55 mph lane change when the gas pedal is temporarily raised? Bottom line is the problem is with the manufacturer, either a failing component and/or an intentional basic logic flaw. Systems logic to shut down should be disabled when actively moving and/or air conditioning, radio etc. should shut down keeping some level of reduced power steering, and power brakes reduced, not complete shut off. Power control module should be hardwired power to OnStar, lights, and horn so that these safety features are intact after an accident You can continue to go nuts trying to diagnose this, or worse pay the dealer for countless grounding evaluations, or several $ 100+ diagnostics evaluations or we can be smart. NHITSA is supposed to take care of safety issues. Some may eventually blame the body control module computer, replace it and charge $ 1,000.00 This is a pretty expensive error message reset, only to have the problem appear again after warranty. Problem is they ignore the countless reports on the internet, and dealer service records. They do not dig in until there is a TBD significant number of formal complaints to the NITSA website. Even though thjis was a NITSA safety recall 17276-2PSR in 2017, they have taken the position to not investigate as of today-rather waiting for more formal complaints or a few deaths -which tends to get their attention. By the way the recall was a software upgrade essentially ignoring the excessive draw for a period of time and maybe even raised the value, both of which are miscalculated as the problem still exists after the recall and re-program. There is a form to fill out. So the best pathforward is to fill out the NITSA complaint forms by everyone who has this problem. If and when they finally assess the true root cause, repairs will be free under recall and those hat have paid to fix the problem (Lucky if it gets fixed) will be reimbursed as was the case in the ABS failures. NHTSA | National Highway Traffic Safety Administration https://www.nhtsa.gov