Brief Summary:
==========

I have been fighting code P1457 all summer (Link to my recent issues:
). This code popped up RIGHT after some work (throttle body/iac cleanup) I got done to fix a problem.

The original problem was car wouldn't start on a very hot day. The only odd thing to have occured that day was I drove in D3 on the highway at speeds between 75-80MPH. After repeated tries to turn the key and crank, the car started finally. To check the health of the vehicle post this catastrophe in making, I went on a loop around the parking lot and highway - the car stalled a couple of times and on the highway, it was an uphill, pressing gas pedal nothing, nil nada...). Over the next couple of days, the car would start or crank. The idle had dropped DRAMATICALLY

The symptoms exhibited seemed like it was the throttle body/IAC that had to be cleaned. I suspect, my mechanic (John) may have changed the idle settings on the IAC during the repair. Even worse, no ILP was performed post work

When i picked the car up, the car was running at 2000RPMs in idle.


Within 2 days of picking the car up, the CEL popped up and code P1457 showed up. I drove the car for nearly a month all the time being aware that it was running excessively rich - that is when the code P0420 first popped up. John explained maybe it was a symptom of other problems I was seeing. No ILP had been done at that point in time.

Gentlemen,

Sorry, this was a long introduction to my P420 problem. I am pretty certain that the "cat" hasnt died perse but may be exhibiting the code because it ran very rich for a month.

Before replacing the cat, can anybody recommend anything that I can do before taking this hit. This link seems to suggest there is more investigation necessary. I have spent more than 1250 this year and my wallet is bleeding. I dont plan on keeping this car beyond early 2015.

Also, can someone please tell me what the idle RPMs should be right after a cold-start? It is 1200rpms right now. But, when the car has been driven around a bit and it is in Park, the revolutions are 700-900rpms. Is this normal?

A couple of obervations:
1. This code showed up after replacing the 3rd clutch pressure switc and duct-taping the canister-vent-valve. After observing the leak on the canister vent valve, I duct-taped the canister vent valve as a short-term fix to prove out the idea that replacing it may fix P1457 problem. Is it possible that fixing the exhaust leak triggered this light to show up?
2. This is the only code show up right now.


please help.

 

From Autozone, this is what I got when the code was scanned:

TP0420 OEM Brand : Honda
Catalyst system efficiency below threshold bank 1

1. A/F ration Concern
2. Air leak near HO2S (heated Oxygen Sensor) Bank 1
3. Ignition system concern
4. Faulty Catalytic Converter

 

The link you posted has very nice information. I'd follow that and see what is going on.

 

Also, check out these threads:

Catalytic Converter dead AGAIN

1998 Honda Accord LX DTC code P0420

P1457 causing the P0420.

 

Roader,

the 2nd link started by rockhound... is very similar to the problem I have. I am glad that P0420 is the only code.

BTW, when I was at the mechanics earlier this week, we connected an OBD2 scanner and measured the voltages Bank 1 sensor 1 and 2. This is my recollection, sensor 1 was changing rapidly and sensor 2 not so much...I didnt think of checking the temperatures at the inlet and outlet of the cat (thanks ericthecarguy, youtube).

i will update with what i find...this is a problem from hell...

 

The P420 came back this evening after 104 miles of driving.

Last weekend, I replaced spark plugs to NGK PZFR5F-11 (had autolite NAPA plugs) and replaced the O2 sensor. The mechanic used a camera (gizmo) and checked the cat, the geometric patterns on cat were showing with no pieces fallen off. I coudlnt tell about coated-substrate (is there a fix for it?)

Folks, I failed inspection (expected) last week and I really need to get this fixed...can anybody please give me any more pointers?

I suspect I still have idle issues (completely warmed car idles at 1000RPM) and can this be a possible cause?

There are no other DTCs other than P0420.

 

Did you fail on tailpipe measurements? Or did you fail simply by having the CEL lit up?

(not that I'll have the answer, but it might help someone else to answer)

 

It failed emissions due to MIL being lit.

What is odd is that OBD II tampering test also failed. I reckon the mechanic reset the codes using the scan tool last time we replaced the canister vent valve + canister set. P0420 came back the following day after 50+ miles of driving. I stopped driving (and used the car sparingly) until the inspection.

ohh, i added a detailed post here - https://www.hondaaccordforum.com/for...0-47222/page4/

 

I added a post here - https://www.hondaaccordforum.com/for...e4/#post340162

quick update: I suspect it was the rear O2 sensor and wrongly changed the front O2 sensor that caused the code to pop up.

well, I have changed both the cat and rear O2 sensor.

I will update in a couple of days if any codes popped and if otherwise, I passed inspection.

 

folks,

I added a post here - https://www.hondaaccordforum.com/for...e4/#post340529

After the new cat and oxygen sensors were replaced - I have since passed inspection.