This situation is the host power of the battery, in this case the battery is out of some problems, or the battery is not powered that is the A\/D conversion chip has been broken, the digital multimeter commonly used A\/D conversion chip is 7106. If the battery is out of power, it will only appear the battery icon and the measurement is inaccurate, will not be garbled, and will not appear -1 when the value is not -1. The condition was that his tissue was unstable and unusable.