NHTSA complaint: 2009 CHEVROLET TAHOE HYBRID — VEHICLE SPEED CONTROL
MY 2009 HYBRID TAHOE ACCELERATES UNCONTROLLABLY ON OCCASION. THE ISSUE ARRISES COMMONLY IN STOP-AND-GO TRAFFIC WHEN THE HYBRID SYSTEM STARTS/STOPS THE GASOLINE ENGINE REGULARLY. I NOTICE IN MANY CIRCUMSTANCES WHEN SWITCHING GAS/ELECTRIC MODES THE VEHICLE LURCHES FORWARD. THE FEELING IS THE SAME AS LETTING OUT THE CLUTCH QUICKLY ON A VEHICLE WITH A MANUAL TRANSMISSION. I HAVE DONE AS MUCH RESEARCH AS I CAN AND IT APPEARS THE PROBLEM POINTS TO ISSUES WITH THE TRANSMISSION FLUID PUMP(S) AND/OR CONTROL MODULES. WHEN THE SYSTEM OPERATES ON THE GAS ENGINE, THE HYBRID TAHOE'S TRANSMISSION RELIES ON AN ENGINE DRIVEN HYDRAULIC FLUID PUMP. WHEN THE SYSTEM SWITCHES TO ELECTRIC MODE, AN AUXILIARY TRANSMISSION FLUID PUMP TURNS ON, DRIVEN BY AN INDEPENDENT ELECTRIC MOTOR. THE LURCH I DESCRIBED RESULTS FROM WHAT I BELIEVE TO BE A FAILING PUMP OR CONTROL MODULE, OR A COMBINATION OF THE BOTH WHICH ENGAGES GEARS WHEN IT SHOULDN'T. THIS LURCH IS RATHER DANGEROUS AS I HAVE HAD TO JUMP ON THE BRAKES MANY TIMES TO AVOID REAR ENDING OTHER DRIVERS. I HAVE SPOKEN WITH SEVERAL INDIVIDUALS WHO OWN, DRIVE OR HAVE DRIVEN THESE GMT900 SERIES HYBRIDS (2008-2013 CHEVY TAHOE/SILVERADO HYBRIDS, GMC YUKON HYBRIDS, CADILLAC ESCALADE HYBRIDS) ALL INDIVIDUALS HAVE DESCRIBED THE DREADED LURCH. SOME SAY REPLACING THE ELECTRIC AUXILIARY TRANSMISSION FLUID PUMP SOLVES THE PROBLEM, OTHERS STILL HAVE LURCHING ISSUES. ONE INDIVIDUAL WHO DRIVES A CADILLAC ESCALADE HYBRID CLAIMED TO HAVE ACTUALLY REAR ENDED SOMEONE
National Highway Traffic Safety Administration — Office of Defects Investigation