There is no code list available, so check these things:
1) Low battery, replace if necessary 2) You are trying to measure an object that is too close, try a more diatant object 3) You are not holding the rangefinder steady and have not gotten a reading off the target. Try an easier, larger, more reflective target as a check. 4) You have an electrical problem requiring repair.
If you are still getting an error, contact Bushnell at 1-800-221-9035 for instructions.