HDHighDef

Hi there, having a super intermittent problem with my vehicle. Sometimes it happens mainly in the winter, sometimes on hot summer days, sometimes its daily, sometimes car will go months without the issue.

Service stabilitrak, traction control, abs and service brake assist messages will come on (both while driving and on startup) AND the car shifts SUPER hard ONLY when these lights come on. The issues (lights/hard shift) will stay on for only a few minutes usually then go off right away, but recently they stayed on for 2 days (but are now out).

Ive had wheel bearings checked, wiring to sensors in the wheel bearings and the only code we've been able to pull in time is history wheel speed sensors (but all look ok as per dealership tech).

My thought is perhaps the abs module itself is inter failing (it seems like its electrical? hard shifting caused by a failed module, maybe tcm?) BUT without being able to duplicate the condition for a mechanic to inspect its a losing battle.

Any help? lol its a long shot, but I love this car, it gets great fuel mileage but its not reliable to do more than around town driving.