2013 Mazda CX5 roughly 64,700 miles on it. Check engine light came on today, took to Auto-Zone to get error code, as well as local dealership and they said that there was no error code?

The light remains on, vehicle drives as it should, but 2 different places are not seeing an error code. What could be the cause of the light coming on?

Let me also add that oil changes etc are performed every 5K miles like clock-work and the next one is scheduled for 66K miles so I am just under 1,500 miles from that. I also checked fluids and everything is at a sufficient level (not low).

  • Try disconnecting the negative cable of the battery and reconnect after a few seconds to reset the ecu and see if it is still on
    – method
    Nov 14, 2016 at 3:31
  • @method - I will try this when I get home this evening. I was not sure if it was a "factory" type deal where it just meant time for tune-up or time for 65K maintenance, etc Nov 14, 2016 at 12:54

2 Answers 2


In a 2013, the Mazda dealer can read more information than the codes that AutoZone ODBII can read. The CAN bus will report more information, such as stored codes that OBDII may not report. I am usually not an advocate of heading to the dealer, but in this case, I would. They can at least do diagnostic and tell you if there are any stored codes. In which case, do NOT disconnect the battery, or you will clear them possibly. I find it is better to know the code and then you can clear it and see if it comes back, than just clear it and not know what it was to begin with.

  • Even thought I took it to a different repair shop as well as Auto-Zone do you think they both use the ODBII reader and the Mazda dealer could still be able to pull a code? Nov 14, 2016 at 20:39
  • Yes, Mazda and Ford use a similar proprietary system that logs extra information in the ECU that is only accessible via the CAN bus and with their special software.
    – RDS_JAF
    Nov 14, 2016 at 21:22

As method mentioned, disconnect then reconnect the battery. This will reset the computer, but after this you will need to drive around for a while before you know if it is off for good or if the underlying issue causes the light to return. You can either look up the drive cycle or drive it around for about 100 miles or so.

Either way, it is certainly strange that neither found an error code. It's got water and oil and trans fluid right? Those aren't low or anything?

  • @tlhIngan thank you it's late and I have been driving all day.
    – Cc Dd
    Nov 14, 2016 at 7:49
  • yes all fluid levels are good. That was one of the first things i checked when I was told no error code was returned. Nov 14, 2016 at 11:33
  • @StarsFlyFreeFromCozyNights then yep pull the battery cable reset the computer drive around until it resets fully and see if anything else flags. Might get a code this time.
    – Cc Dd
    Nov 15, 2016 at 0:10

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