Failed Emissions Test Reading Meanings?

Anyone have ideas what these readings mean and why I failed?

System Monitors;
engine misfire - ready
fuel system - ready
comprehensive comp - ready
catalytic converter - not ready
evaporative system - not ready
heated 02 sensor - ready
oxygen sensor - not ready
secondary air system - not supported
ac refrigerant - not supported
egr flow - not supported
heated catalyst - not supported


mil command status - OFF

I have a P0137 code. I have had the battery disconnected to trouble shoot headlight problems 2 weeks ago and installed a new alternator a little over two months ago. I do not drive the car much (maybe 15 - 20 miles per week) but should have had enough for a drive cycle.

The car was warmed up by the time I got to the test facility. 2006 3.3 V6 Sonata.

Here is the correct drive cycle to reset the readiness monitors for your vehicle.


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I am in the process of learning OBD II better. P0137 indicates a failed Oxygen sensor. With a failed O sensor it will probably not run the other monitors thus a failure for verification. And, with a defective O sensor, there is no way that car would pass clean air requirements if they would check it.

Either replace that sensor or get it to someone to replace it for you.

Catalytic converter takes a lot of driving at a speed above that which one can do in town with low speed limits.

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Wow, more involved than I thought it would be. Thanks

Will do tomorrow. Have the sensors and 02 sockets, was just waiting for a warmer day. Thanks.

Just connected the OBD 2 and now have four codes!! P161B P1295 P2106 from searching seems to be a throttle sensor issue. And a P0137 in pending codes. It’s always something.

I looked at the 02 sensors live reading and s1b2 reads at 0.000 - 0.050 the other 02 sensors all are 0.100 - 0.700 's. I take it when it does not reach at least 0.100 that is low voltage (p0137)?

The cat, evap, and o2 sensor readiness monitors reporting “not ready” is probably why you flunked the emissions test. As long as the check engine light isn’t on and all the readiness monitors says 'ready" you might be able to pass now, even with the pending p0137 problem.

re o2 sensors. There are different types, but the most common one outputs a changing signal between 0 and 0.8 volts as the engine is idling. Most of the time it is either close to 0 or close to 0.8. It should be nearly 50% of the time for each in any event. If the computer needs to inject more or less gas to hit that 50% compared to how much it thinks it needs to, that could be the reason for the p0137. A reading of the fuel trims would be next in line towards the diagnosis. According to the phot above, you short term fuel trims appear to be ok. What about the long term?

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Yeah, they all show ok (except catalyst and evap show “inc” I guess that is incomplete?) in I/M Readiness and the B1S2 did go over 0.100 once or twice. So 0.100 is 0.1 volt?

If you want here is what the OBD 2 reads…

The beginning is with key on and the end part of this video (video shakes) is when I was driving.

It looks like one o2 sensor is behaving normally, ranging from near 0 volts to near 0.8 volts w/roughly a 50% duty cycle, but the other is a pretty low voltage all the time. It’s S1 that behaves normally, and S2 that is on the low side as I recall. There’s different technologies of o2 sensors however, and maybe S2 is a different type than S1. S1 is usually the one before the cat, and S2 is after. S1 is primarily used to set the fuel/air mixture, and S2 is primarily used to verify whether the cat is working or not. Do you have two cats? If so, how do s1 and s2 behave on the other bank? The way shops diagnose the s1/s2 relationship, they have a scan tool that plots the two signals side by side over time. They can usuallly tell if the cat is faulty or a sensor is faulty by looking at that plot. You may need to secure one of those type of scan tools, or consult someone who has one.

Yes, 0.100 probably means the output of the o2 sensor measures 0.1 volt at that measurement time.

The throttle problem may be related to the o2 sensor. The computer may be trying to prevent damage to the cat – which is very expensive to repair — by limiting engine power until the o2 sensor problem is corrected.

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From what I’ve read there are two rear cats. When I was under there it looked like they branched off, so I take it that were the two rear.

There should be four 02 sensors. Two in front in the engine bay and two in back of the cats on the underside. Though I only noticed the b1s2 on the passenger side.

Tomorrow I will try again to remove and replace the sensor (also an oil change) then clear the codes and do a drive cycle. Hopefully the new sensor solves the problem.

That seems like a good plan. Best of luck. Hopefully it will clear up all the symptoms and the dtc’s too. Keep us informed of any progress.

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