# Service Engine Soon Light Is On- Why?



## rokeia (Oct 29, 2021)

Hi All -

Hopefully, nothing so dangerous, but I am uncomfortable about the maintenance of my 2001 LR Disco II. 
All the readings are typical for my sweet DII. The vehicle is going on perfectly fine. The engine is working smoothly... vehicle has been carefully maintained regularly.

But I read the gas cap can trip the Service Engine Soon light is on? I checked it. It was slightly loose, then I tightened it but the light is still on.

Am I doing something incorrectly? I am looking for a pretty simple solution.


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## rogoman (Dec 16, 2004)

Use a portable scan tool to clear the DTCs and your "service engine soon" light should go out.


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## 2016 Versa (Sep 24, 2019)

rokeia said:


> Hi All -
> 
> Hopefully, nothing so dangerous, but I am uncomfortable about the maintenance of my 2001 LR Disco II.
> All the readings are typical for my sweet DII. The vehicle is going on perfectly fine. The engine is working smoothly... vehicle has been carefully maintained regularly.
> ...


I'd use a code reader to pull the trouble code or codes then reset the ECU and see if the same code(s) returns. If it doesn't great, if it does the code number should give you an indication of where to start looking for problems.


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## VStar650CL (Nov 12, 2020)

If the loose cap was causing it, the light won't reset itself until you take a drive and then let it sit overnight. The tank has to be between 1/4 and 3/4 full. Under those conditions, the ECM will run an EONV test (Engine Off Natural Vacuum) after the vehicle has been parked awhile. When the tank holds vacuum, the code will reset and the light will go out. The only way to turn it off immediately is with a code reader.


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