To provide a car door lock which can display failure in a hole sensor chip and also failure in the conductors leading from the hole sensor chip to an electronic evaluation device or in the current feed part and which can thereupon avoid malfunctioning satisfactorily.

A car door lock is equipped with a lock mechanism, locking mechanism, and electronic controlling and/or checking device. The controlling and/or checking device has a hole sensor chip, which emits the first information signal having a high amperage level and the second information signal having a low amperage level. The electronic evaluation device distinguish the second information signal, which exceeds the lower amperage threshold Isu and lies under the upper amperage threshold Iso, and a third information signal which has an amperage level in a certain range from zero. Generation of information having an amperage level in the range from zero to the lower threshold Isu originates from a failure in the hole sensor chip, the conductors leading therefrom to the electronic evaluation device, or in the current feed part of the chip.