2004 Toyota Prius: adaptive cruise control problems

Filed Jun 20, 2011 · Brakes · 84,380 miles · VA

While drivimg under cruise control at approximately 70 MPH, a continuous loud beep occurred, accompanied with the following warnings on the dashboard: red "brake" warning and yellow "((!))", "ABS" (antilock brake system), and "vsc" (vehicle stability control) warnings. Attempting to pull over and stop, the brakes had no power assistance but, fortunately, could be operated under heavy foot pressure. After pulling over and stopping and restarting the engine, all the warnings and the beep were still there while the car was driven to a safer location at a gas station. Braking was still entirely under foot pressure only. As this was in canada, driver turned off the engine while trying to decide the next course of action. After a few minutes, the engine was again started in order to move the car slightly in the parking lot (to get away from a puddle) and all systems, including brake power assistance, were now operating normally with all the warnings off. The problem has not recurred. The car was taken to the dealer about two weeks later and the diagnostic report states, "could not duplicate customer's complaint". Thus, no repair was done nor further action was taken by the dealer.

Filed May 11, 2010 · Engine · 133,939 miles · TX

Failure of inverter coolant pump occurred without warning during normal driving conditions. This is apparently a common problem occurring at many different mileage intervals for other owners. Immediate significant loss of power and several warning lights illuminated. Cruise control and A/C went offline. Requires replacement which in this instance was $605.00.

Filed Jul 8, 2009 · Engine · 126,000 miles · TX

This happened to me and cost over $700 to fix: 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.

Filed Jul 2, 2009 · Engine · 160,000 miles · IL

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.

Filed Mar 13, 2006 · Acceleration, Brakes · 12,995 miles · IN

Dt*: the contact stated upon entering a highway at 60 MPH, the vehicle accelerated rapidly. Brake pressure was applied, but the vehicle did not stop accelerating. Each time brake pressure was applied; there was a loud grinding noise. Although the cruise control was not engaged, the cruise control was manually activated in an attempt to stop the acceleration. With brake pressure applied, the contact managed to exit the freeway using the exit ramp. When the vehicle slowed, the park button option was pressed and the vehicle stopped. There was no further acceleration or grinding noise. The vehicle was towed to the dealer and is awaiting inspection of the problem. The consumer also stated, when she applied the brakes, the pedal became soft and went to the floor. Updated

Filed Mar 29, 2004 · Brakes · 2,389 miles · MO

Reported to toyota on 2/7/04 file #200402110133. While driving on the highway, 70mph, cruise control on, both my wife and myself have accidentally bumped the gear shift knob with our hand and put the prius into dynamic braking mode (dbm). The semi-truck behind me almost ran me over before I could get the car back into drive. Very dangerous!!! The brake light does not come on during dbm. Toyota should change the software to make a delay in the gear-shift for dbm similar to shifting into neutral?