NHTSA Complaint #10275528 — 2004 TOYOTA PRIUS

FAILURE OF INVERTER/CONVERTER COOLANT PUMP. HYBRID VEHICLE HAS 2ND COOLANT LOOP FOR HIGH VOLTAGE INVERTER/CONVERTER. FAILURE OF INVERTER/CONVERTER COOLANT PUMP ALLOWS INVERTER COOLANT TEMPERATURE TO RISE WELL ABOVE NOMINAL. AT A CERTAIN TRIGGER POINT HYBRID CONTROL ECU SETS A TROUBLE CODE THAT IMMEDIATELY DISENGAGES OPERATION OF INVERTER/CONVERTER (AND SIMULTANEOUSLY DISENGAGES CRUISE CONTROL AND A/C, WHICH RUNS OF ALTERNATING CURRENT PRODUCED BY INVERTER). IMMEDIATE IMPACT IS A SUDDEN LOSS OF VEHICLE DRIVE POWER AS INVERTER/CONVERTER SUPPLIES TO ELECTRICITY TO MOTOR GENERATOR 2 (MG2) WHICH IS DIRECTLY CONNECTED TO DRIVE WHEELS AND SUPPLIES NEEDED MOTIVE FORCE TO MAINTAIN HIGHWAY SPEEDS (ICE ALONE IS INSUFFICIENT). ALSO INVERTER/CONVERTER COOLANT LOOP PROVIDES COOLING FOR MG2 & MG1. CONTINUED OPERATION OF VEHICLE WITH FAILED INVERTER/CONVERTER COOLANT PUMP COULD RESULT IN CATASTROPHIC FAILURE OF MAIN ELECTRIC DRIVE MG2 AND SUBSEQUENT LOSS OF MOTIVE POWER. PUMP FAILURE OCCURS WITHOUT WARNING, ALTHOUGH THERE MAY BE A BRIEF PERIOD OF INTERMITTENT PUMP OPERATION/NON-OPERATION PRIOR TO FINAL FAILURE. THE FAILURE SEEMS TO BE THE RESULT OF EITHER A DEFECTIVE INVERTER/CONVERTER PUMP ASS'Y OR ONE INSUFFICIENTLY ENGINEERED TO WITHSTAND CONTINUOUS OPERATION IN SUCH A CRITICAL COMPONENT. PUMP FAILURE OCCURRED AFTER APPROXIMATELY 160,000 MILES, ALTHOUGH HAS BEEN KNOWN TO OCCUR IN OTHER INSTANCES AS EARLY AS 32,000 MILES. SUDDEN LOSS OF POWER AND DISENGAGEMENT OF CRUISE CONTROL AT INTERSTATE HIGHWAY SPEEDS COULD CAUSE DRIVER TO LOSE CONTROL OR TO BE UNABLE TO SAFELY STEER TO A SAFE BREAKDOWN LANE. *TR