Honda Ridgeline Owners Club Forums banner

1 - 10 of 10 Posts

·
Registered
Joined
·
18 Posts
Discussion Starter #1
I have an 08 RTX with 165k miles on her. Lately, I have had intermittent P0420 CEL warnings... After reading the ODB2, it is the "Bank 1" O2... Here is the question... The Catalytic Converter has 2 sensors. An upper and a lower.... Which one do I replace?

Is there a "more likely to be.." one?

Sal
 

·
Registered
Joined
·
379 Posts
The output of the upper actually affects the air/fuel ratio corrections made by the ECU. The lower only indicates whether the cat is operating properly.

I think it's more likely to indicate the second one as being the problem. At least that's what Mazda told me when I had a P0420 code and I wanted my cat replaced under warranty. I also smelled rotten eggs which indicated the cat was failing. I haven't looked, but I think the lower sensor would be easier to replace as well.
 

·
Registered
Joined
·
4,171 Posts
If you're going to do this work yourself, buy the Denso sensor, not Bosch.

Chip H.
 

·
Registered
Joined
·
534 Posts
On this same topic. My '08 with 128K miles started having the check engine light come on (and off) severial times over the last couple of months. My local dealer says it is the lower CAT. I do not smell the rotten egg smell. How do I know it is not simply the sensor? As always I appreciate the help.:act018:
 

·
Registered
Joined
·
5,620 Posts
On this same topic. My '08 with 128K miles started having the check engine light come on (and off) severial times over the last couple of months. My local dealer says it is the lower CAT. I do not smell the rotten egg smell. How do I know it is not simply the sensor? As always I appreciate the help.:act018:
Only by changing the O2 sensor.
 

·
Registered
Joined
·
534 Posts
Only by changing the O2 sensor.
That would be cheaper than the CAT. I guess the error code can't break down the difference between the sensor and the CAT...Thanks!:act024:
 
1 - 10 of 10 Posts
Top