My check engine light has been coming on and off lately and i notice while its on, the ECO mode light does not come on. When the CEL is not on, the ECO light comes on as it should. Its an 07 Odyssey, with just over 100k miles. I just recently replaces timing belt,water pump, and serpentine belt. Now this is happening. I have noticed a loss in mpg, averaging 18 on hwy. Just got back on a 800 mile trip and the oil was 1/2 qt low. CEL code reads P0420. Im trying to mention everything i can, hopefully its not the catalytic converter after only 6 years. Thanks for any help

 

Is the CEL flashing when it comes on?

If so, then the system is realizing the car has a misfire. It may be a coil and/or plug going bad. If it is misfiring, it can cause that side of the engine to run rich on that cylinder which can cause the converter to get excess fuel and clog.

If it isn't flashing, it may be that the converter is just starting to go bad and it will pass at times and fail at other times.

Any loss in power or acceleration? When does the light come on (overdrive and going up an incline, etc...) and is it solid or flashing?

 

No, it does not flash. I have not found that there is a certain time it comes on. I also have not noticed any power loss, just the mpg.

 

It does sound like that converter has just gone bad then.

 

CEL has been off all day today. Everything is back to normal. Only thing i did was add fuel cleaner/octane boost.

 

Is it normal a converter would go bad on an 07, only 6 years old?

 

Cats can go for 1 year or 12 years its just your luck.

 

rear bank is the ususal , is about 3 hours to replace it