Honda catalytic converter troubles.

[jsharp]

My sister called last night to ask about some problems they've been having with their son's 99 Civic and I thought I'd run it by everyone here.

They purchased the car about a year ago and the catalytic converter had just been replaced. The previous owner said the CEL had just come on and an independent garage replaced the converter with an aftermarket one. They talked to the guy who did the work and he confirmed this plus they had the service and warranty paperwork for the converter and the installation.

They drove the car until July, maybe 15K miles tops. The CEL came on again. A garage checked the code and it came up catalytic converter. Thinking the previous replacement had gone bad for some reason, they had it replaced for free on warranty with the same aftermarket variety as before.

Now, 3 months later, the CEL is on again. She took the car to Autozone to get the code read and surprise! it comes up as a bad converter yet again. ***, 3 in a year? Something is not right.

The kicker to this is the cost of the parts. An aftermarket converter is $400-$900 depending on where you price it. The O2 sensors, 2 required, run $90-$180 depending on which one you're looking at and where you buy it. Using real Honda parts a dealer quoted them $1600 for the repair but didn't specify what all he'd be replacing.

The car right now has about 110K miles and is in good condition. They've spend a few $$ on tires and other repairs so they would like to get this resolved and keep it. I'm wondering if the downstream O2 sensor is bad and the engine management system just "thinks" the converter is bad. Or ??

They live 3 hours away so I can't go with them when they take it in to talk to the mechanic, but I'd like to help them if I can.

Any suggestions??

 

[FowVay]

If you're getting a P0420 code (generic) then the two items of concern are the catalyst or the secondary heated O2 sensor.

I would venture a guess that it is the post-converter heated sensor. Otherwise you will get a code for the O2 sensor independent of the catalyst fault.

Honda has their own trouble codes aside from the generic codes and they're normally far more accurate at diagnostics than the generic codes are. Pay to have a dealership scan the codes and also have them scanned with a generic reader and post the DTC's for us to see. If the Honda code comes up as a '67' then it is the secondary heated O2 sensor.

Keep us posted.

 

[brianl703]

Sometimes, vacuum leaks can cause P0420 or P0430 codes. As can exhaust leaks (before the post-cat sensor).

 

[Mud]

Be aware that some codes point you to the area of concern, but that you may need to break this down further.

Example: I had a code thrown on my 95 Crown Vic. Autozone said it was "EGR". I knew that bad EGR valves are actually not that common on the 4.6 engines and that most EGR complaints are from a DFTE (or DPTE I forget the letters!) sensor that reads high/low pressures in the exhaust - this reading is sent to the ECM which then activates the EGR valve. The sensor can get moisture in it and fail. I decided to go on this info, replaced the sensor, cleared the codes, and all has been well since.

What FowVay said - point is that the "P" series codes are industry standard and somewhat generic. The mfg's have their own codes in addition to the P codes. You need to sometimes drill down a bit to find the root cause of the code.

Sounds like you have been replacing the worng component. Not being a wiseguy, but unless it's obvious, don't let Autozone diagnose your car's codes, or at least verify what they are telling you.

 

[jsharp]

Thanks guys.

Mud - It's as I said in my original post. I live 3+ hours from them and I've never even seen the car, let alone replaced any parts on it. Neither my sister or bro-in-law are too car oriented. I'm just trying to help them out.

I think the guy who's worked on the car has misdiagnosed the problem. I just wanted to see if my hunches about what might really cause this were reasonable.

I understand the generic code thing. My 4Runner gave a P0171 code at one point. "Bank 1 lean" It was nothing more than a dirty MAF.

I'm going to suggest they run it by the Honda stealer and pay them the $$ to get some real codes.

I'll post what they find out here. I'll bet $$ it's NOT a bad converter...

 

[passcord]

Check if any other codes present with P0420/0430 and resolve these first. You can remove code by pulling negative cable and fuse to ECM. And see if it return again. By the way it is not effect driveability at all. So if there no emision testing, you may ... but of course it is bad for environment. On side note aftermarket cat is not so great. Pretty much all hi-flow cats give a code. AM cats are smaller than OEM, some have after cat HO2S sensor in the wrong place,exhaust piping made in the way so cat not get anough heat. Look like CAR SOUND brand or Magnaflow cats close to OEM.
Search yahoo or google for code "P0420" and you get the picture.

 

[seotaji]

you can pull the codes yourself by jumping the service connector with a paperclip located on the passenger side under the dash.footwell area.

it'll flash out like morse code.

flash flash flash pause flash flash, etc...

 

[Mud]

As far as I know you cannot use a jumper wire to flash the CEL on OBDII cars.

Being a long distance away and not repair folks, as you said, best bet is to head them to a dealership.

 

[jsharp]

quote:

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Originally posted by Mud:


Being a long distance away and not repair folks, as you said, best bet is to head them to a dealership.

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That's been the problem all along. I'm too far away to help much, but I'd still like to do what I can to make sure they don't get screwed any more on this.

Thanks all for the replies. When they find out more I'll post what we learn...

 

[Ray H]

Aren't catalytic converters covered for 8 yrs./80,000 miles under the federal Emissions Control warranty?

 

[jsharp]

quote:

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Originally posted by Ray H:
Aren't catalytic converters covered for 8 yrs./80,000 miles under the federal Emissions Control warranty?

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With, 110K miles, they're over mileage unless the warranty is 8 years and 80K miles. Nice thought though. It sure would be nice to have Honda fix it for free...

 

[kingrob]

quote:

---

Example: I had a code thrown on my 95 Crown Vic. Autozone said it was "EGR". I knew that bad EGR valves are actually not that common on the 4.6 engines and that most EGR complaints are from a DFTE (or DPTE I forget the letters!) sensor that reads high/low pressures in the exhaust - this reading is sent to the ECM which then activates the EGR valve. The sensor can get moisture in it and fail. I decided to go on this info, replaced the sensor, cleared the codes, and all has been well since.

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I had the same thing on my 93 Crown Vic. The code kept coming back EGR but it ended up being an arced spark plug wire.

 

[PandaBear]

Honda runs fine on generic sensor if you are willing to crimp your own (I did mine, OBD2 with 2 sensor, not hard).

It can't be cat lasting so short, I am still on my original after 165k miles and they weren't known for problems. Even a cheap aftermarket should last you at least 30k at least.

I suggest checking out the ECU and do a smog check to see if it really is the CAT. Sounds like someone modified the engine or fuel/timing and the engine is running rich (ricer?), very common symptom. Some ECU chip on ebay just dump 20% more fuel and blind all sensor warnings.

Check the plugs on all 4 cylinders and see if any or all are fouled.

The last and very important thing, check a honda site like honda-tech.com or temple of vtec. It may sound silly but thats where most Honda infos are at.

 

[jsharp]

quote:

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Originally posted by seotaji:
you can pull the codes yourself by jumping the service connector with a paperclip located on the passenger side under the dash.footwell area.

it'll flash out like morse code.

flash flash flash pause flash flash, etc...

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I didn't know you could pull OBDII codes that way. In this case it doesn't matter though. They are NOT car repair people and I'm too far away to look at it myself.