On Dec 18 2013 Zero notified the NHTSA of recall to
properly handle continuing glitches in 2012 and 2013 bikes. You can read about the
earlier glitch for 2012 bikes in another post.
For better readability, everything between '****' is a quote from Zero's defect report.
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DESCRIPTION OF DEFECT:The subject motorcycles have a controller firmware that may react to infrequently encountered signal faults by discontinuing controller power to the motor. Should one of these faults occur while the motorcycle is being ridden, the controller's response may result in an inadvertent quits-while-running condition, which could lead to a crash.
CHRONOLOGY OF EVENTS:On 09/12/2012, Zero Motorcycles concluded that certain 2012 model year motorcycles had a motor encoder position signal that could drift over the extended use of the motorcycle. Should the encoder signal drift too far, it could fall beyond the signal limits expected by the motor controller. This condition could cause the motor controller firmware to respond to such a signal fault by discontinuing power to the motor, resulting in the inadvertent loss of power of the motorcycle, which could lead to a possible crash. In response to the conclusion of its investigation, Zero Motorcycles determined that a defect related to motor vehicle safety existed and declared a voluntary recall program (12V-455). The remedy in this program involved a new controller firmware and configuration, which compensates for the possible drift of the motor encoder position signal to ensure it remains within the limits expected by the controller.
Over the next several months, Zero Motorcycles received reports of 2012 and 2013 model year motorcycles that exhibited similar quits-while-running behavior. Since the analysis of each of these reports revealed a variety of unrelated faults as the root cause of the inadvertent power interruption, on 09/20/2013 Zero Motorcycles personnel traveled to Sevcon's headquarters in the United Kingdom to better understand the reason behind such behavior (Sevcon Limited is the manufacturer of the subject controller and developer of its firmware). During the ensuing investigation after this meeting, it became clear to Zero Motorcycles and Sevcon that these random, infrequent and unrelated signal faults could not be avoided in the lifetime of the motorcycle, and that the controller firmware needed to deal with these faults in a different, more reasonable manner.
On 12/05/2013, Zero Motorcycles completed its internal investigation of this concern and concluded that 2012 and 2013 model motorcycles built with a Sevcon controller prior to 11/08/2013 have firmware that could respond to infrequent signal faults by discontinuing controller power to the motor, which could lead to a quits-while-running situation. Zero Motorcycles executive management considered this information and determined that a defect related to motor vehicle safety existed.
Zero Motorcycles is not aware of any accidents or injuries caused by this condition.
DESCRIPTION OF THE PROGRAM TO REMEDY THE DEFECT:The remedy of this defect is for Zero Motorcycles dealers to update the suspect vehicles with revised controller firmware that deals with these infrequent faults in a way that does not result in an inadvertent quits-while-running condition.
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Topic: Zero issues recall for controller cutouts for 2013 bikes (Read 7086 times)