P0456 and now P0421 error codes

[kkim]

I’ve had a P0456 on and off for several months now. Had it checked out by an independent mechanic and the dealer with no real root cause. The independent mechanic tried to do a smoke test which resulted in a bunch of fault codes which the dealer eventually reset. The dealer also did a pressure test and no issues,

I replaced the gas cap with OEM already. Since last weekend trip up to Tahoe, I’m seeing a P0421. I’ve found a lot of people complaining about this issue after a ski trip and Tahoe was not particularly cold (~ 40 degrees). Anyone else had these issues and can they be related somehow? The car appears to run fine.

Any recommended course of action? This vehincle is within the VIN number range for the cylinder head and coolant in the oil issue.

2019 CX-5 Signature with 46K miles

 

[ADS-B]

Check the oxygen sensors. You can stop by any auto parts store and ask them to run the test. It’s free of charge. If it turns out you have an issue with one of the oxygen sensors, I advise to replace the faulty one sooner rather then later. In the long run it may develop in a catalytic converter issue and that would cost you more.

 

[kkim]

Now, I got a P0171. The engine is sputtering or racing. WTF? Time for that new Bimmer the wife keeps talking about.

 

[Warez09]

I’ve had a P0456 on and off for several months now. Had it checked out by an independent mechanic and the dealer with no real root cause. The independent mechanic tried to do a smoke test which resulted in a bunch of fault codes which the dealer eventually reset. The dealer also did a pressure test and no issues,

I replaced the gas cap with OEM already. Since last weekend trip up to Tahoe, I’m seeing a P0421. I’ve found a lot of people complaining about this issue after a ski trip and Tahoe was not particularly cold (~ 40 degrees). Anyone else had these issues and can they be related somehow? The car appears to run fine.

Any recommended course of action? This vehincle is within the VIN number range for the cylinder head and coolant in the oil issue.

2019 CX-5 Signature with 46K miles

I had this issue on my Honda HRV and couldn’t find the root cause. I would reset the code and it would be off for a while before it popped back on. So long story short, my battery died and I replaced it, I never had the code pop up again.

 

[kkim]

Turned out to be a bad purge valve. Ended up just selling the car to the dealer.