Honda Odyssey check engine light

[DeafBrad]

Hi,

The check engine light came on in my 2001 Odyssey. The first time it came on shortly after the 2 gallon gas warning light came on. The light stayed on for a while until I gassed up. This has happened several times. Today the check engine light came on after my wife gassed up the van.

I have a code reader here so I checked for the codes. The codes are p1491 and po420. I figure these codes are related... 1 problem is causing both codes. Any ideas out there what the problem could be? Otherwise the van runs ok... no hesitation or anything.

Thanks for your time,

Brad

 

[Chris142]

One is an egr fault and the other the hated cat code. Fix the egr first and see if they both stay off.

 

[Warstud]

Quit running it low on gas. I never let mine get below a 1/4 of a tank.

 

[dogememe]

Originally Posted by Warstud
Quit running it low on gas. I never let mine get below a 1/4 of a tank.

While I am in the "treat 1/4 tank as empty" camp running it down to E is not causing the OP's problem and really it's not that important. Yes the fuel pump will run cooler on a fuller tank but there is constantly fuel flowing through it so it's not a big deal.

 

[DeafBrad]

Originally Posted by dogememe
Originally Posted by Warstud
Quit running it low on gas. I never let mine get below a 1/4 of a tank.

While I am in the "treat 1/4 tank as empty" camp running it down to E is not causing the OP's problem and really it's not that important. Yes the fuel pump will run cooler on a fuller tank but there is constantly fuel flowing through it so it's not a big deal.


The first time the check engine light came on after the gas light came on, but the other 2 times it was around 1/4 tank or so. Even if it were somehow related to letting the gas get low I would still want to fix whatever the problem is.

 

[DeafBrad]

Originally Posted by Chris142
One is an egr fault and the other the hated cat code. Fix the egr first and see if they both stay off.


Is it possible the egr valve is not opening which is resulting in the cat not being able to clean up the exhaust gasses, hence the code for the cat?

 

[Hall]

Originally Posted by DeafBrad
The first time the check engine light came on after the gas light came on, but the other 2 times it was around 1/4 tank or so. Even if it were somehow related to letting the gas get low I would still want to fix whatever the problem is.

It's not the cause of your issue so it's sometimes best to just ignore off-topic and unhelpful responses like that....

 

[Trav]

Clean out the EGR passages with something like an old speedometer cable first. They sell long small diameter flexible steel brushes, look on amazon.
The EGR may be almost totally plugged so you may need to replace it if you cant get it clean or the code wont clear, its not that expensive for this one about $55 for a SMP.

The P420 is a cat code which normally indicates a bad cat but with this one running higher chamber temps due to lack of EGR the ECM may have adjusted things to compensate for possible pinging by pulling timing and adjusting injector pulse width. I have pulled O2's out of these engines with EGR passage issues that were black as coal and almost clogged.

Seeing as you should replace O2 sensors when you change the cat I would say that seeing as these are very inexpensive for this car it may be worth changing them first, if it does need a cat just use them with the new one.

 

[anndel]

P1491 - EGR https://www.youtube.com/watch?v=OIp4yWN1Ay8

which could be causing the P0420 DTC

P0420 - Catalyst System Efficiency Below Threshold Bank 1

Read more: https://www.autocodes.com/p0420_honda.html

Check both O2 Sensors and check of cat converter is getting clogged if fixing the EGR hasn't cleared the P0420 DTC.

 

[JMJNet]

May not be a bad idea to do a Seafoam through the vacuum emission lines after cleaning the EGR.

 

[CharBaby]

Is there any chance that the Odyssey was gassed up with the engine running?
This seems to cause the CEL to appear on the dash according to a friend of my who owns an early model Pilot w/same engine. Just asking!

 

[DeafBrad]

I cleaned out the egr passage. The passage was plugged solid. So far as I know the check engine light has not come back on!