# Lost communication with MCU and MCU 'mcu' shutdown: Timer too close **URL:** \ **Category:** General Discussion\ **Created:** [September 29, 2023, 10:07pm UTC](https://klipper.discourse.group/t/lost-communication-with-mcu-and-mcu-mcu-shutdown-timer-too-close/10745 "2023-09-29T22:07:55Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![EddyMI3D](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/eddymi3d/32/1981_2.png) [@EddyMI3D](https://klipper.discourse.group/u/EddyMI3D)\ **Post date:** [September 30, 2023, 6:35am UTC](https://klipper.discourse.group/t/lost-communication-with-mcu-and-mcu-mcu-shutdown-timer-too-close/10745/2 "2023-09-30T06:35:01Z")
Hello @MikiFX ! You may have a look on these: > [@Timer too close](https://klipper.discourse.group/t/timer-too-close/6634): > > Timer too close Background A “Timer too close” error occurs when the MCU is asked to schedule an action at a time that is already in the past. This typically results from delayed communication between the host and the MCU - for instance, if the host was busy or the message was blocked en route. warning Important: Klipper can identify what command was too late, but cannot determine why the delay occurred. The root cause is often external - such as USB congestion from a webcam or high system … > [@Timeout with MCU / Lost communication with MCU](https://klipper.discourse.group/t/timeout-with-mcu-lost-communication-with-mcu/6639): > > Timeout with MCU / Lost Communication with MCU Background This error occurs when the Klipper host receives no response from a connected MCU to its regular “heartbeat” or other command messages for several seconds. It often appears in conjunction with the [Got EOF when reading from device](https://klipper.discourse.group/t/got-eof-when-reading-from-device/6638/1) error. warning Important: Klipper only detects the symptom - a communication loss. It is not capable of determining the root cause, which may lie outside of Klipper’s control (e.g., hardware faults, power i… --- _[View the full topic](https://klipper.discourse.group/t/lost-communication-with-mcu-and-mcu-mcu-shutdown-timer-too-close/10745)._