My CEL turned on this week and a buddy of mine at work lent me his $20 OBD II reader and helped me set up my smart phone with the free Torque Lite App. I was able to read the fault code, and the link said it was "catalyst system efficiency is below threshold limit".

When I went to the displays for the O2 sensors, I only get live data from one O2 sensor.

My question is this: Does anyone know if this could be pointing to the problem? Shouldn't there be 2 oxygen sensor outputs available to view in the Torque Lite App?

Any and all advice would be appreciated, I'd like to keep this DIY and avoid my local dealer (stealer) and their outrageous prices for parts and service (they are set to charge me $78 just to read the code and tell me what they need to do to fix it)

 

Are you saying that you get a voltage reading from one and a 0 from the other?

 

To properly diagnose you should find out if any DTCs are stored in the history [freeze frame]. Not sure a $20 code reader will do that... no idea what a Torque Lite App is.

You might want to invest in a factory service manual if you want to avoid your local dealer. There is a reason they charge money - they know what they're doing and how to fix things.

There's also a forum search tool.
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There are a few Codes associated with P0420 that might be tripped at the same time but not necessarily be currant:

P0137, P0138: Secondary HO2S (Sensor 2)
P0141: Secondary HO2S (Sensor 2) heater
P0300: Random misfire
P0301－P0304: No. 1, No. 2, No. 3, or No. 4 cylinder misfire detected

These need to be addressed first before drawing conclusions.

Poor quality fuel might also be the culprit.

K_C_

 

I get an output from the bank 1, sensor 2 (oxygen sensor). All of the other oxygen sensor channels have no output. I'd guess this is normal, because most cars don't use all of the 8 channels available in the OBD protocol.

 

How many miles does the car have. May need a new cat converter. U don't have a cat delete do u?

 

Thanks for the info. I fully agree that the local shop is competent, it's just that one of their core competences is to gut my wallet like a fish whenever I've gone in there. It's not that they're dishonest, they're just not bashful about selling parts at ~30% over list price. I know I can't expect to pay Bernardi prices when I go there, but at least they could keep it reasonable for us DIY'ers. I consider them my 1st choice if I can't fix it myself.

 

74000 miles on a 2007 sport. No cat delete...totally stock.

 

Welcome to the freakworld!

See if you can pull history codes. It will help you figure things out. Bad fuel is the bottom line, however.

Keep us posted.

 

KC, Your right about bad fuel here is a link Bad Gasoline Causes Performance Problems

 

Try going to Autozone. They should be able to pull codes for you and at no charge. On another note. Do work for MTS Paul?

 

There are a few things you can try a p0420 is a clogged Cat. converter. There is a thread some where on here that they put it in 3rd gear and took it on the highway and for a hour and heated the cat up trying to cleaning it out.

Then you can try this before replacing. Fixing Bad Catalytic Converters With Inefficiency Code P0420 - YouTube

 

Scotty Kilmer - you gotta love that guy!!

I'll agree on the cat being the problem after being sure there's no other associated codes that might also contribute to the issue. A new $$cat$$ isn't something you simply want to throw at a car if there's other issues.

How you be Silver, lovin that LX????

 

My car is OK, but my wife's car is not at 17000 miles. I am beginning to question Honda reliability. RFG gas is suppose to have the required additives but I am thinking it doesn't and that there might be more ethanol in the regular gas. I went through a quarter tank of gas going to and from work yesterday. I go a full week in my car and still have a 1/3 in the tank winter and half in the summer. Premium is a better product around here and some brands are better yet.

Work is killing me but love my new truck. Still getting use to it. My old truck gets better mpg with a engine almost twice as big. So there is something about a bigger motor still being more efficient.

 

My 1996 Cadillac Sedan Deville 4.6L 275HP NorthStar V8 would give me 28MPG at turnpike speeds.
Saw 30 once down in Mississippi after switching to Shell.
Sometimes I miss that car, but not too often.

You know and understand the issues with fuels at the pump better than most.
It's always been a smoke and mirror game to me.
From the prices we pay to the product quality coming out of the nozzle.
I don't see any indications that anything's about to change - the oil boys go on.

 

I just notice the difference because of my 12 hours a day driving. Gasoline is not all the same except its made from oil. The one link said that for every octane increase there is a 20 percent less yield but that would mean premium would cost 15 dollars or more if that was true. I always said to try different brands and octane. Some regulars might be better but not around here and mid grade might be all you need. ORI is a real problem and there is a lot of variables. They are raising the ethanol to E15 to help offset some of the octane issues but if they lower the octane of the base fuel the same problems will occur. Its funny in 1997 they said going from 89 to 87 did not produce engine knock but they did not tell you that all cars have knock sensors from 1996 on part of OBDII which turned back timing and eventually used more gas.

Bigger motors have the potential to get better mpg because its torque at lower rpms that move the vehicle. Once at speed less throttle and fuel is need to maintain.

 

Have u been having problems with this car in the past to question the reliability?

 

My Honda no, but I use premium. My wife has the same car as me and she has had lots of problems. Rough running motor with bad mpg and she drives the car quickly and uses regular. She wont listen to me and so I when I get gas I fill up with premium and it runs a little better but because she adds regular next tank the problem never gets resolved. The TPMS light is always on and had the rack n pinion replaced which wrecked the front tires. At 17000 miles I think the brakes need to be replaced already too.

When I drove the car yesterday to work it went through a 1/4 tank which is really bad considering I can get to and from work 2-3 days using the same amount.

 

Premium gas isn't gonna resolve the issue. Higher octane gas is to prevent detonation. A lot of guys that mod their cars will start messing with the ignition timing which will cause detonation with lower octane gas which is why they go higher.

Is ur car or her car the one with the problem?

 

Its hers, the stock Honda ecu has 12 fuel maps with the same for timing. It also has corrections maps too it looks up. Honda ecu can run 87 to 96 octane the engine is tuned to find the maximum spark advance before any knock is likely. This is called the 'knock ignition limit'. Knock sensors retards the timing and the unburnt fuel shows a lean condition which then the ecu adds more fuel.

Premium gas 91/93 is where the timing and fuel control is set for MBT which is the point the car is most efficient.

 

So hers is running rough. Does it have other codes or had other codes in the past.