2nd Generation GE8 Specific DIY: Repair & Maintenance Sub-Forum Threads discussing repairs and maintenance you can do yourself on the 2nd generation Honda Fit (GE8)

Check Engine Light Came on at about 150,000 miles

Old 08-28-2014, 12:52 AM
Thread Starter
Join Date: Sep 2011
Location: New York, New York
Posts: 218
Check Engine Light Came on at about 150,000 miles

My check engine light came on at about 150,000 miles. When the check engine light comes on and the engine is running well there are usually two reasons. 1) Gas cap isnt tight OR 2) Emissions system error. I took it to the Autozone and the code came back P0420. This code relates to emissions.

P0420 Honda Catalyst System Efficiency Below Threshold Bank 1 OBDII Engine Light Trouble Code | Engine-Codes.com

My experience is that parts like the O2 sensor and the catalytic converter are wear away components. Prior to my Honda Fit, I owned two Toyotas. One Toyota needed an O2 sensor at around 50k miles and the other a catalytic converter at 175k miles. Sometimes there is corrosion and loose connections in the exhaust system which could also cause the problem.

In any event, this error code will not effect the drivability of the vehicle, but it will fail an inspection. My inspection is not due until 2016. The cost to fix this issue would probably be about $300-700 therefore it is unlikely I will have this fixed soon. What I will do is try to reset the light by disconnecting the battery and see if it comes back on.
Old 08-28-2014, 01:59 AM
5 Year Member
Join Date: Jul 2009
Location: SF Bay Area
Posts: 670
if you got the codes read, you should've just reset the code at the same time with the reader.

Might as well pick up a OBD2 adapter. If you have a smart phone, these are now cheap. Probably less then the gas (and time) going to autozone a few times.
Old 08-28-2014, 11:07 AM
Steve244's Avatar
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Join Date: Aug 2009
Location: Georgia
Posts: 3,658
have you had your plugs changed and valves adjusted?
Old 08-30-2014, 10:03 PM
demouser's Avatar
Join Date: Mar 2014
Location: Chicago burbs
Posts: 185
If you want to fix it on the cheap, the spark plug anti-fouler trick might work. I've done it on 3 cars so far to get rid of P0420, and it works like a charm.
Old 09-07-2014, 03:14 PM
Santiad's Avatar
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Join Date: Nov 2009
Location: Atlanta, Georgia
Posts: 824
Check plugs


I too drive alot for work (124k on my 09) throughout the NJ and NYC area and I also recieved that CEL around 120k.

I tried cat- cleaners and went so far as to buy an extra cat converter just in case. Then I went to Honda to address some service issues when they found 3 of my plugs were loose.

Perhaps your cat is going bad, but perhaps another part of your fuel system is allowing too much unburned fuel through the sensors, giving you that error message.

While I was going through it, I watched video after video and forum after forum and none referenced the spark plugs.

Just a heads up...

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