HAD C7 Z51 STICK 2014 AND HAD PROBLEM WITH TRACTION AND STABILITY CONTROL. AFTER PURCHASED THE CAR I RECOGNIZED THAT WHEN ACCELERATION BIT FASTER THERE WAS BACK AXLE, PARKING BRAKE AND SOME OTHER WARNINGS. IT HAPPENED ALWAYS WHEN ACCELERATED BIT FASTER. WINTER STAB WORKED OK. BUT NOW IN SUMMER I LOST CONTROL ON HIGHWAY DRIVING 50 MPH ACCELERATING ON WET ROAD AND LOST CONTROL AND HIT GUARD RAIL. THERE WAS NO STABILITY OR TRACTION CONTROL WHAT SO EVER. I WAS IN ECO MODE WHICH HAS NORMAL STAB/TRAC CONTROL. I BROUGHT TO DEALER WHEN WARNING LIGHTS COME UP, BUT DEALER SAID IT IS NORMAL NO WORRY EVERYTHING IS OK. BUT IT WAS NOT WORKING AT ALL!!