> For the complete documentation index, see [llms.txt](https://knowledge.illumina.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://knowledge.illumina.com/instrumentation/nextseq-500-550/instrumentation-nextseq-500-550-troubleshooting-list/000006373.md).
# Troubleshooting pre run checks with Temperature sensor check failed: Board 0/1 on NextSeq 500/550
In rare instances, it is possible for the NextSeq 500/550 to fail to successfully complete the pre-run check with a "Temperature sensor check failed: Originally caused by: Temperature is out of range for Board 0 and/or Board 1 Temperature Probe" error message.
The Main Board (MPCA) assists with connecting the onboard computer with the instrument hardware and includes two temperature sensors integrated into the MPCA. This error may display as a result of a communication error, or potentially a defective sensor.
**Troubleshooting steps:**
1. Power cycle the NextSeq 500/550.
* Search Knowledge Base Article **How to Perform a NextSeq 500/550 Power Cycle**.
2. Repeat the run setup.
3. If error returns after a power cycle, or returns on subsequent run setup, contact [Illumina Technical Support](https://www.illumina.com/company/contact-us.html#/united-states/technical-support) for additional assistance.
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| *For any feedback or questions regarding this article (Illumina Knowledge Article #6373), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000006373%20-%20Instrumentation%20\&body=Dear%20Illumina%20Technical%20Support,%0D%0A%0D%0A)*.* |
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