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[SR-71Blackbird]

Hi all,

Got a question re the codes stored on the ECU that can be read with the paperclip test.

Lets say the engine management/warning light comes on when you are driving and then the car is parked and cooled etc.

Then you go for another drive on a different day and no light comes on and no problems.
If you read the code after the no light journey then will the code that caused the Engine light to come on the day before be shown? Or will it not be shown because the latest journey did not have a light on?

If the engine light comes on should you check the code immediately with the paperclip to find out what it is then?

Thanks

Alex

[Diamond Black Geezer]

I have heard:

-the codes are stored forever
-the codes will clear after you turn over the ignition/engine 20 times
-you specifically need a Tech2 code reader to clear codes, never ever a plop-cum
-you can use a plop-cum to clear them, it's fine

[SR-71Blackbird]

Anybody know for sure?

Thanks

[TheBoy]

Varies with the code and the ECU.

Some stay forever, until cleared with a code reader.
Some disappear as soon as fault fixed.
Some disappear after a set number of clean runs.