Engine Error Code PO420 ... Any suggestions? - Honda Prelude Forum

swiftstreetlude · 03-31-2008, 09:28 PM

Ok heres my story:

Back in OCT 06, my engine light came on and showed Engine Error Code PO401-EGR Insufficient Flow Detected
. After months of trying to figure out how to fix the problem ( as showed in this thread -> http://www.honda-acura.net/forums/sh...d.php?t=252827), I finally got my EGR Valve Ports cleaned in FEB 07 and that solved the problem.

Now, its March 08 and just recently my engine light came back on. I didnt pull the codes at first, because I figured it might be the EGR Valve again and just swapped out my old EGR Valve with a used one I bought from a 97 prelude. It seemed to work fine for a week with no engine light, but just yesterday it came back on. So I took it to my local Sears to have the engine codes pulled and they showed P0420 - Catalyst System Efficiency Below Threshold

Engine Error Codes List - http://www.troublecodes.net/honda/hondaobd2.shtml

Now a few questions:
1. Will the EGR Valve affect this code? Because it seemed to work fine for a week when i did change it out.
2. If not, then what else do I need to do in order to get this problem resolved?

01 Prelude SH (blue)
111,000 Miles
All Stock (except rims)
No Major Problems for 4 years until now:
1. A/C Motor (?) is going out. Makes a loud rattling sound when turned on.
2. Small oil leak from somewhere. Its all over my oil pan and other parts underneath the engine.
3. Engine Error Code po420 - Catalyst System Efficiency Below Threshold (Bank 1)

Thanks for any help.

Solid · 03-31-2008, 09:44 PM

That code can be caused by the secondary O2 sensor or from a bad catalytic converter.

It can also be caused by an exhaust leak.

DRR1998 · 04-01-2008, 02:47 PM

Dood - In Cali a 420 is code for too many bong hits...Ha, not funny huh.Was the car fully warmed up? I've heard you get best results if the car was run at freeway speeds for ~15 minutes right before testing.

swiftstreetlude · 04-01-2008, 03:49 PM

Well took it to my honda repair shop (not dealership) and they concluded that it was the catalyatic converter. Where are some websites to where I can order one?

silverbullit · 04-02-2008, 03:42 PM

My best suggestion would be to order a Random Technology high flow cat. It's the best bang for the buck, considering the cost of an OEM replacement. Here's a site Lightning Motorsports - Random Technology Catalytic Converter Prelude 96-00 2.2 & 2.3L All - 184-20001 These are my local guys, and they tend to have pretty good prices.

boymeetsfence · 04-02-2008, 04:11 PM

get a test pipe and search spark plug foulers.... no more CEL

Solid · 04-02-2008, 04:17 PM

Quote:

Originally Posted by silverbullit

My best suggestion would be to order a Random Technology high flow cat. It's the best bang for the buck, considering the cost of an OEM replacement. Here's a site Lightning Motorsports - Random Technology Catalytic Converter Prelude 96-00 2.2 & 2.3L All - 184-20001 These are my local guys, and they tend to have pretty good prices.

These often will still throw a code.

It would be cheapest to get a carsound / magnaflow. Then to be sure two two drilled out anti-foulers for the o2 sensor.

swiftstreetlude · 04-03-2008, 11:50 AM

Well I wanted to get a direct fit one. Found an Eastern Catalytic Coverter here thats "says" its a direct fit.

Also, I was driving to work today and the engine light cut off. Could that mean its not the converter and actually the rear or front sensor?