My check engine light was on, so I went to an O'Reiley's to buy a diagnostic tool. Basically, they had two versions of the same brand: one that just checked the engine codes and gave you the translation, and one that could read codes and also delete them that cost almost $30 more. After asking a friend, he confirmed that the same basic pricing structure exists across most diagnostic tools.

Why is this the case? Is there a specific reason that erasing codes has to cost so much extra money?

  • I costs more to produce. Also as with any consumer device the more features it has the more it costs.
    – Moab
    Apr 30, 2016 at 2:47
  • What brand of car do you have?
    – race fever
    Apr 30, 2016 at 3:46
  • 2005 Dodge Stratus. I got my diagnostic tool, it was a loose gas cap, no worries. Just curious about the price structure. Apr 30, 2016 at 3:57
  • Then just disconnect the battery negative for about 15 minutes and that code will go away.
    – race fever
    Apr 30, 2016 at 21:50

1 Answer 1


A read command is the same for all OEM's. The clear command is not. It is supposed to be but there are differences particularly in the early years of OBD11. It has to be tweaked and checked for many different models. Also any command that asks the PCM change its state requires much more care than a read only request.

I have used cheap scanners that did some really weird things when the clear code command was sent.

  • Does not explain why they cost more, which is the question.
    – Moab
    Apr 30, 2016 at 14:27
  • @Moab My apologies, I thought it was implicit in the idea that it takes much longer to write and vet the code. Apr 30, 2016 at 18:09
  • Don't worry, I follow. Never occurred to me that erasing codes could be that difficult, but I would buy it. Apr 30, 2016 at 22:54

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