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'99 Odyssey catalytic converter problems

5K views 13 replies 5 participants last post by  William Wiles 
#1 ·
I recently had my 2nd catalytic converter installed in 2 years & the check engine light just came on again. Of course I'm also due for inspection. My mechanic is telling me I have to use only premium gas to not ruin my Honda catalytic converter. Anyone else been told this? It doesn't seem right since the manual says to use any gas over 87 octane.
 
#2 ·
Another brilliant grease monkey. Too bad Honda doesn't send their mechanics to school.
Is the code still the Catalytic converter? A good article with information on diagnosing the problem. http://www.troublecodes.net/articles/catfailure/

To get it through the testing you could probably reset the code and run several drive cycles to set the continuous and non continuous tests. Then have it tested before the code comes back.
 
#3 ·
I just glanced at the article you suggested and it's way more technical than I can handle. I don't think the code was specifically cat. converter but that was their solution. This time (cat. converter only 2 months old) he showed me how the converter looked like it had alternating bands of color -- thus his conclusion that low octane gas was causing it to clog up again. I've looked at a couple of threads here about folks installing new EGR, but don't think I have the ability for that. Plus I've got to get the van inspected this month. Any other suggestions? Sounds like this mechanic (my office manager's boyfriend) is a waste.
 
#5 ·
Something is ruining those converters and it is not the low octane gas! An good technician will search out the cause of a catalyst failure before sacrificing a new one to the same fate. It may be that your oxygen sensors are used up and allowing the system to provide a fuel mixture which is too rich (sure death for a converter). There could also be some engine misfiring which would also contaminate a converter. You need to take the van to someone with the diagnostic skills and equipment to solve the problem properly, so that you will have a properly running van and not one which will "just get through the inspection". Good luck.

Jerry O.
 
#7 ·
Drive cycle tests. There are several tests the computer runs during warm up and driving that determine the emision state of the engine. When you reset the computer the completion state of these tests are reset to no. It takes several drive cycles (through warmup and driving) for these tests to complete. Depending on your driving it could take a week for all of them to complete. Most inspection places today check the computer with an OBDII tester and if any of the tests are not complete it will fail. So if you do have a solid failure you can't just reset the computer and have it inspected.....
 
#9 ·
sorry about that duplicate threads -- I did put it into 2 threads. Was still finding my way around the forum.

From all the reading I'm doing it doesn't sound like it's easy or straightforward to diagnose whether it's a clogged EGR, an oxygen sensor or truly the cat. conv. I'm really in a quandary what to do. The "new" cat. conv. was only put in 45 days ago. My reliable mechanic has an ODB2 "compliant" scanner but all he's coming up with is P0240.
 
#10 ·
As I mentioned in this forum earlier, I had a few times the same code for CAT. I reset the light & I put Premium Gas + Gumout. It goes away. You problem might be different from mine. I always try the cheapest & DIY first. Not sure it's a good idea.

These damn things are hard to guess. I guess Honda made it mechanics a way to make money from us :)
 
#12 ·
Yes, I've searched for P0240 (using numeral "0") on this forum and generally through Google. My mechanic tells me that if there were any secondary codes they would have printed out. The only code that is showing is the P0240. He tells me he's got a $8,000 computer/scanner for finding out these codes, but he doesn't have the fancier equipment to check on O2 sensor outputs or the like. Also doesn't have a means of testing tailpipe emissions & doesn't know of any other mechanics locally who do either, since he's asked around.

All I'm saying is that there seem to be as many theories/opinions on what to fix in what order as there are people who have had the cat. con problem. Do you have any suggestions?
 
#13 ·
egads said:
PO420
That's the CAT code.
You mechanic may be reliable, but if he is not up to speed on these things, he is grasping at straws. If you have not, do a search with just the code.
The second O is a capital O the fourth is a zero. Here's one thread:

http://www.odyclub.com/forums/showthread.php?s=&threadid=29346

If there is no computer at the mechanics' then he may never fix this.
I knew you'll come up with helpful info as always!

Two Thumbs Up for egads



:cool:
 
#14 ·
Find another mechanic. The problem is beyond looking at codes. The mechanic needs to understand the intricasies ( not good at spelling) of the fuel system. He wasted his money on the $8000 tester as he aparently can't go beyoud it's readout of codes. Fuel trim needs diagnosed. EGR flow needs looked at. O2 sensers need checked. As mentioned misfires need checked. Injecters could have bad spray patterns due to wear or contamination. Try some injecter cleaner inthe tank. Reset the code and see how long it takes to come back and you could sneak the inspection in that time.
 
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