A method for signaling a malfunction of a position determination device (PV), which has a GNSS receiver (GE) and a mobile radio receiver (ME), characterized by the following method steps: - identify an error time range such that in each of several position determination processes carried out within the error time range either a) a position determination quality of the GNSS reception identified by means of the GNSS receiver (GE) falls below a predetermined GNSS quality threshold value, or b) a position is identified by means of the GNSS receiver (GE) with being established that all positions identified within the error time range describe a spatial standstill of the position determination device (PV) during the error time range; - detect both a first mobile radio reception characteristic and at least one second mobile radio reception characteristic of the mobile radio reception of the mobile radio receiver (ME) during the identified error time range, wherein the first mobile radio reception characteristic is measured at earlier time and the second mobile radio reception characteristic is measured at later time within the error time range; and - decide, depending on the first and at least the second mobile radio reception characteristics, that a malfunction of a position determination device is signaled, if an evaluation of the detected first and the second mobile radio reception characteristics results in a position determination device having moved during the identified error time range. - identify an error time range such that in each of several position determination processes carried out within the error time range either a) a position determination quality of the GNSS reception identified by means of the GNSS receiver (GE) falls below a predetermined GNSS quality threshold value, or b) a position is identified by means of the GNSS receiver (GE) with being established that all positions identified within the error time range describe a spatial standstill of the position determination device (PV) during the error time range; a) a position determination quality of the GNSS reception identified by means of the GNSS receiver (GE) falls below a predetermined GNSS quality threshold value, or b) a position is identified by means of the GNSS receiver (GE) with being established that all positions identified within the error time range describe a spatial standstill of the position determination device (PV) during the error time range; - detect both a first mobile radio reception characteristic and at least one second mobile radio reception characteristic of the mobile radio reception of the mobile radio receiver (ME) during the identified error time range, wherein the first mobile radio reception characteristic is measured at earlier time and the second mobile radio reception characteristic is measured at later time within the error time range; and - decide, depending on the first and at least the second mobile radio reception characteristics, that a malfunction of a position determination device is signaled, if an evaluation of the detected first and the second mobile radio reception characteristics results in a position determination device having moved during the identified error time range. <EOS>