Hello,
Thank you for your query.
Normally, when the engine is started, the voltage in the battery increases, and in some vehicles, voltage spikes can occur. These spikes may affect the values read from some sensors. This could be happening in your case, to validate this, we suggest you measure the voltage on the FMB120 analog input when the engine is started and compare it with the value shown on the configurator, the values should similar.
Kind regards.