# Check engine light

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When the [check-engine-light](https://help.sbtinstruments.com/encyclopedia/maintenance/check-engine-light "mention") appears, schedule [preventive-maintenance](https://help.sbtinstruments.com/encyclopedia/item-register/service-agreement/preventive-maintenance "mention") as soon as possible.
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The check engine light appears when your BactoBox® requires [preventive-maintenance](https://help.sbtinstruments.com/encyclopedia/item-register/service-agreement/preventive-maintenance "mention").

The check engine signals that your BactoBox® setup *approaches* a failure mode. It allows you to schedule preventive maintenance before it is too late.

The check engine appears in the upper right corner in [user-interface](https://help.sbtinstruments.com/encyclopedia/software/user-interface "mention").

<figure><img src="https://4216107837-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FeYTtd7c0A325muFr5lMW%2Fuploads%2FI6mdP9PR5mikjlSdHNcm%2Fimage.png?alt=media&#x26;token=718716c7-741e-4813-bcda-9dc2e5705ab0" alt="" width="375"><figcaption><p>The check engine light appears in the upper right corner in <a data-mention href="../software/user-interface">user-interface</a>.</p></figcaption></figure>

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## Preventive maintenance is part of your [service agreement](https://help.sbtinstruments.com/encyclopedia/item-register/service-agreement)

Your [service-agreement](https://help.sbtinstruments.com/encyclopedia/item-register/service-agreement "mention") offers 24 month warranty and includes 2 × [preventive-maintenance](https://help.sbtinstruments.com/encyclopedia/item-register/service-agreement/preventive-maintenance "mention").
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## What triggers the check engine light

The check engine light appears if any of these are true:

* It's been a year since the last [preventive-maintenance](https://help.sbtinstruments.com/encyclopedia/item-register/service-agreement/preventive-maintenance "mention")
* You've run 2000 programs (e.g., measurements) since the last [preventive-maintenance](https://help.sbtinstruments.com/encyclopedia/item-register/service-agreement/preventive-maintenance "mention")
* The latest QC test shows that your BactoBox® setup approaches a failure mode

## Can I use my BactoBox® while the check engine light shows?

**Yes.** The check engine light signals that your BactoBox® *approaches* a failure mode. In other words, your BactoBox® setup still works as intended even when the check engine light appears.

{% hint style="success" %}
When the [check-engine-light](https://help.sbtinstruments.com/encyclopedia/maintenance/check-engine-light "mention") appears, schedule [preventive-maintenance](https://help.sbtinstruments.com/encyclopedia/item-register/service-agreement/preventive-maintenance "mention") as soon as possible.
{% endhint %}