# Check engine light
{% hint style="success" %}
When the [Check engine light](/protocols/maintenance/check-engine-light.md) appears, schedule [Preventive maintenance](/encyclopedia/item-register/service-agreement/preventive-maintenance.md) as soon as possible.
{% endhint %}
The check engine light appears when your BactoBox® requires [Preventive maintenance](/encyclopedia/item-register/service-agreement/preventive-maintenance.md).
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 [Dash](/encyclopedia/software/user-interface.md).
{% hint style="success" %}
## Preventive maintenance is part of your [service agreement](/encyclopedia/item-register/service-agreement.md)
Your [Service agreement](/encyclopedia/item-register/service-agreement.md) offers 24 month warranty and includes 2 × [Preventive maintenance](/encyclopedia/item-register/service-agreement/preventive-maintenance.md).
{% endhint %}
## 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](/encyclopedia/item-register/service-agreement/preventive-maintenance.md)
* You've run 2000 programs (e.g., measurements) since the last [Preventive maintenance](/encyclopedia/item-register/service-agreement/preventive-maintenance.md)
* 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](/protocols/maintenance/check-engine-light.md) appears, schedule [Preventive maintenance](/encyclopedia/item-register/service-agreement/preventive-maintenance.md) as soon as possible.
{% endhint %}
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