EGR by Standard Motor Products. Remind me again how to test the egr to see if it's working. Also; I have a question: Why if there is passageway blockage due to carbon build up; why wouldn't it run bad all the time instead of sporatic intervals? Just curious

 

Your first code was P0401, which means plugged EGR passages.

Your recent code is P1491 means the engine computer is not seeing the proper %open signal from the EGR valve. Your EGR valve is directly commanded open/closed by the engine computer. Older accords EGR valves were controlled by a vacuum source that was controlled by the engine computer. Seanjordan is confusing your electronic EGR valve with older accords that used vacuum.

Blocked EGR passages are not your problem according to you engine computer.

Below is a video link to a Honda Odyssey with same code (Note - maybe not the same issue) on youtube. This guy own's his own repair shop and knows how to diagnose vehicles. This will give you an idea of the level of testing he does to diagnose a problem. We can walk you through some of his tests to help identify the problem.

A code means that a problem exists in the circuit, so your problem can be the EGR valve, the wiring, or the PCM (aka engine computer).

 

PAhonda; appreciate your replying to my problem. I've watched this video before and this guy is good; I wish I had him close to my house. I believe he would have already found my problem. I just put a new Egr on it about 10 days ago and I changed out the ecm with one from a salvaged vehicle about a month ago. With this being said; what should I do next? I don't have the knowledge to troubleshoot mine the way the guy in the video does.

 

The new error code is about bad feedback information from the EGR valve. But that being the case, couldn't that mask the additional problem of clogged EGR passageways? I just think that the P1491 doesn't necessarily rule out clogged passageways.

 

JimBlake thanks for your reply. When the weather gets warmer I'm going to give them passageway's a good cleaning. It seems that if the passageway was clogged or dirty it would run bad all the time instead of like it does. Maybe; I"m just thinking out loud.

 

I think either way, it would stumble or do something funny whenever the PCM calls for the EGR valve to open. I don't know the whole scheme for when that's supposed to happen.

 

Can I just unplug the egr or put a metal plate under it and isolate it from the engine to see if it will help or can that be accomplished?

 

Did the old and salvage PCM both not have the check engine light turn on for 2 seconds when you turn the key to the II position and not try to start the car?

 

I haven't seen any CEL with either pcm ; only one I see is the maintenance required light. I replaced some burnt out bulbs in the dashboard cluster and I was going to replace the Cel but I couldn't find a place for it.

 

UPDATE: Well I've attempted putting in a new remanufactured ECM in it but the dealer couldn't get it to program. He couldn't get the key immobilizer light to come on the dashboard when he was trying to program it. He said there was no power coming out of the ecm. Is the key immobilizer light supposed to come on when you put in a new ecm?