Just yesterday error code P0126 popped up on my CX-5. I read the code and cleared it. Now in hind sight I wish I had not done that as the dealer would want to see code. Do you think if problem persists the light will come back on? Or have I just screwed myself?

If it does not come back on can dealer retrieve a history of codes the engine has thrown???

So far I have driven about 70 kms and the code has not come back. Running at about 75 Celsius in weather that is around 2 Celsius. I am not sure what normal running temperature should be.

Thanks a lot.

 

The DTC is in the permanent file until the condition causing the DTC is corrected.

Is after 1-4 complete engine cycles which is parking no run for at least 8 hours is one cycle, the is causing the check engine light to activate and you finding the DTC is not corrected the check engine light will activate and you can retrieve the newest DTC.

The DTC you posted may also effect the I/M monitors which you can only reset you can not clear them until the issues are corrected. That is also an area the service technician ( I did state technician) or Mazda factory trained mechanic should look at when scanning the ECU .

You need to achieve 2 things on a cold start getting into the correct reporting of the HO2 which you have and reaching the normal coolant temperature of minimum 130f .

 

You were 100% correct. After over nighting for 4 nights where it was parked for 8 hours it produced the code again. Came on this morning.

Mine is running cold so thermostat is most likely stuck open. Car still under warranty so I expect Mazda will fix at no charge. I will contact them today.

Thanks for you advice.

 

Let's hope Mazda takes care of it on your visit to the service department.