Why were the issue codes (not) detected?

• Why does it say "No Issues Detected" when my check engine light is on?
• Why does it detect some codes when there's no light on?

Check Engine Light is on but no codes detected

For Starter, we'd like to make it clear here that this device is only able to detect Check Engine Light related issue codes.

If you want to learn more about all the other kinds of lights and their meanings, please refer to

What are the meanings of different car dash icons?

More importantly, please scan your car when the device is connected, that is when Dashboard page shows the live data. Otherwise, it'll just tell you something based on your historical data.

The device diagnoses and pulls data from the vehicle using OBD II protocols and, as you may not know, car manufacturers, apply different kinds of OBD II protocols in different makes and models. We are trying our best to develop and test our products to make the device & app compatible with most vehicles, however, we can't guarantee full coverage.

If you are 100% sure that your Check Engine Light is on, yet ZUS is telling you "No Issue Detected" that might indicate currently, that your car's protocol isn't 100% compatible. In this case, please send us a log via Settings > Help & Support > Feature Request, so developers can look into it further.

No light is on but codes detected

Some of you may encounter the problem that ZUS says your car has some issues, which your car does not. This might also be caused by the OBD II protocols. All the data is detected and diagnosed under the general standard protocols, which means your car is in default to have some features. Samely, if you have any questions, please send us a log via Settings > Help & Support > Feature Request, so we can help you fix them.

The best way to solve any issue is through constant communication and investigation. Throwing a negative review on the App Store/Google Play won't help solve the issue cause we won't be able to know the details we need to solve the issue. We do appreciate your message to us and we will make sure that all your feedback & request is well received and followed up.