VOID 14, or Voided Analysis, indicates that the instrument detected a possible interfering substance. The characteristics of the signal from each sample are compared against a set of internally stored characteristics from the last calibration or accuracy check.  If the fuel cell signal being analyzed during a sample is significantly different from the stored characteristics, the instrument is designed to reject that test, flagging it as VOID 14.
This could be caused by two scenarios:
The instrument was presented with a sample with an interfering substance that responded on the sensor but in a manner that was detected to be significantly different than the response to ethanol during the previous calibration or accuracy check.
The normal aging of the fuel cell between calibrations or accuracy checks has resulted in a significant shift in the rate of response to a sample with ethanol in it.
To determine if the latter is the issue, calibrating the instrument with a known ethanol standard will reset the stored characteristics that the instrument is comparing the subject result to. If the error condition persists there is likely an interfering substance at play and steps should be taken to try and isolate it.
If this does not resolve the VOID 14 issue, the instrument may need to be returned to Intoximeters for service.