# Errors – Causes and Corrective Measures

Cause | Remedy
--- | ---
Temperature monitoring indicator (k) and warning indicator (j) light up, it is not possible to take a measurement
The measuring tool is outside of the operating temperature range, or has been subjected to large fluctuations in temperature. | Switch the measuring tool off and allow it to adjust to the ambient temperature before switching it back on. It is only possible to take exact measurements if the temperature inside the measuring tool remains constant.
Radio interference indicator (i) and warning indicator (j) light up
Measurements are impaired by electric, magnetic or electromagnetic fields (such as mobile phones, laptops or tablets near the measuring tool). | If possible, deactivate all tools whose radiation could interfere with the measurement and switch off the corresponding functions or tools.
Warning indicator (j) flashes
The measuring tool has developed a fault and is no longer functional. | Send the measuring tool to an authorised Bosch after-sales service centre.
Metal object indicator and continuously high amplitude in the measuring indicator (b), even though there is no metal object near the measuring tool
The factory calibration is no longer valid (e.g. if the measuring tool falls from great height). | Manually recalibrate the measuring tool see Recalibrating the Measuring Tool.
Light-up ring (1) does not light up when it is positioned on the surface
The surface cannot be detected because the sensor area (17) is dirty. | Clean the measuring tool with a soft, dry cloth and re-start the measurement.
Contact with the wall or surface may not be detected due to particular wall properties (e.g. a very dark surface). | Position the measuring tool on the surface. For manual wall detection, press and hold the metal/electricity (4) and wood (5) buttons simultaneously until the light-up ring (1) is lit (for approx. 3 s) and an audio signal sounds. Then perform a measurement as usual. Note: Before taking the next measurement on a different surface, you must reset the manual wall detection. To do this, switch the measuring tool off and on again.