Hello,

been fighting an issue for months on my 2015 Honda CRV. Keeps having code 420 from what they tell me is a bad downstream converter. Confirmed by dealer and local mechanic. Changed it out. Light came back on. Now from the diagnostic reader same code but upstream O2 sensor staying at 2.0. Changed both upstream and downstream sensors. Light is back on again. Does anyone out there have any experience or a direction we could try on this. I know that some will say live with the light but cannot use the remote starter when light is on.

Thanks,
Bernie

 

What is the code?

 

welcome to the forum. Just a heads up on the O2 sensors, if they were after market sensors your code will come back. Need to use factory sensors.

 

Code has been and stilll is 420

 

Is the sensor OEM? How long between no code and code? If it's been running bad it can destroy the cat bed.

 

Sensors are aftermarket. So had code 420, changed downstream cat. Same code after 40 miles. One week later changed both upstream and downstream o2 sensors. Same code 420. Wouldn’t the code change in some way if problem is one of the parts is bad? Also what is fuel trim as that is what they are going after next?

 

You need to use OEM sensors.

 

So, let me address the use of non oem sensors. The issue was fixed and I still have the aftermarket sensors and cat installed. Saved a bunch of money by not trying to fix this problem any further by myself or the advice of this forum. Took it to the dealer dropped it off and said make the code 420 go away. Also told them what work was done. They did some stuff that only Honda can do like using what they called rapid capture and cutting out one device at a time till the issue was found. They did have Honda factory involved for the cut out programming. So at the end of day the WU cat was bad. That would also be known as the upstream cat. I can’t say that all aftermarket parts are fine but the denso sensors I installed checked out just fine on the resistance test. And yes the dealer installed an aftermarket, magnaflow, cat. Thanks for all the advice.

 

Not a manufacturer dealer. No way.