NHTSA Preliminary Evaluation PE05029

ODI OPENED PE05-029 BASED ON 33 REPORTS OF ALLEGED GASOLINE ENGINE STALLING ON THE SUBJECT VEHICLES.THE SUBJECT VEHICLES ARE GASOLINE/ ELECTRIC HYBRID VEHICLES THAT CAN BE OPERATED IN GASOLINE OR ELECTRIC MODES, OR A COMBINATION OF BOTH DEPENDING ON THE POWER DEMAND.ALL REPORTS ALLEGE THAT THE GASOLINE ENGINE SHUT DOWN SUDDENLY WITHOUT WARNING.SOME OF THE COMPLAINANTS REPORTED THAT THE VEHICLE CONTINUED TO OPERATE USING THE ELECTRIC MODE FOR A PERIOD OF TIME AFTER THE GAS ENGINE STALLED AND SOME REPORTED THAT THE VEHICLE SHUT DOWN AT THE SAME TIME THAT THEY FELT THE GAS ENGINE STALLED.SOME CONSUMERS REPORTED THAT THEY WERE ABLE TO RESTART THE VEHICLE EITHER IMMEDIATELY OR AFTER ALLOWING THE VEHICLE SIT FOR A SHORT TIME, WHEREAS OTHERS REPORTED THAT THEY HAD THEIR VEHICLE TOWED.DURING PE05-029, ADDITIONAL FAILURE DATA WAS IDENTIFIED AS NOTED IN THE FAILURE REPORT SUMMARY ABOVE.THE COMPLAINT DATA REPRESENTS INCIDENTS WHERE ENGINE STALLING WAS ALLEGED OR WHERE THE VEHICLE WAS ALLEGED TO HAVE ONE OF THE VARIOUS CONDITIONS THAT CAUSES THE GAS ENGINE TO STALL.IN ITS AUGUST 26, 2005 RESPONSE TO ODI'S INFORMATION REQUEST, TOYOTA IDENTIFIED VARIOUS CONDITIONS THAT COULD CAUSE THE SUBJECT VEHICLES TO EXPERIENCE A GAS ENGINE STALL.IF THIS HAPPENS, THE DRIVER IS ALERTED BY AN AUDIBLE SOUND AND VARIOUS WARNING LIGHTS.THE VEHICLE WILL CONTINUE TO OPERATE IN THE ELECTRIC MODE AND THE ELECTRICALLY-POWERED BRAKE AND STEERING OPERATION WILL CONTINUE TO FUNCTION NORMALLY. ANALYSIS OF THE WARRANTY DATA INDICATED THAT OVER 97% OF VEHICLES EXPERIENCING A GAS ENGINE STALL RESULTED FROM AN ISSUE WITH THE PROGRAM LOGIC IN THE ELECTRONIC CONTROL MODULE (ECM) SYSTEM, WHICH MAY CAUSE THE ECM SYSTEM TO NOT START THE GAS ENGINE WHEN REQUIRED.AS A RESULT, THE VEHICLE WILL ENTER THE LIMITED OPERATION MODE DESCRIBED ABOVE.THE MAJORITY OF THE ODI COMPLAINTS ALSO INDICATED THAT THE DRIVER EXPERIENCED THIS CONDITION IN CONJUNCTION WITH THE ENGINE STALL. DURING OCTOBER 2005, TOYOTA INFORMED ODI THAT IT