Car passed inspection with defective catalytic converter.How was this possible?

You did not give enough information about what you did not pass on emissions. Usually it is the co2. If that is the case, it is either the sensors at the catalytic convertor need replacing, or the catalytic converter itself. You can get sensors at the wrecking yard but NOT catalytic converters.

Trouble Code: P2096

Downstream Fuel System 1/2 Lean
Possible Causes:


Exhaust leakEngine mechanical problemO2 Sensor has failedO2 Sensor signal circuit or return circuit problemFuel contamination

Lean Fuel Mixture
Defective EGR System
Defective Catalytic Converter (CAT)
High Engine Mileage
Engine Overheating

Because of lack of information (data) about your inspection, it is hard to tell where the failure is.
For more information about changing catalytic converter. The price can be 10 times different.
The highest quota I got was over $1400 (the golden smog station), the lowest was below $200 (found by state division where I asked for compensation due to old car -- since I cannot go there directly, I paid $325 fro an agent to do it). Dealer was asking for $700.
After changed a home genie catalytic converter, which worked better then the original manufactured till car is dead in another 10 years, I brought it back to the golden smog station for free re-test. The technician did not believe that is a new, and inspected to verify that is true.
This homegenie catalytic converter passed a number of smog tests till car is dead after another 10 years.
BTW, the original manufactured catalytic converter failed on the very first smog check at year 6 or 7 after can was bought, so it is possible you had a failure catalytic converter, but inspection result may tell.

this should help.
http://www.obd-codes.com/p0441

What type of Honda Civic do you have? There is a difference between the LX and EX civic exhaust systems. And your vehicle will not pass inspection with your check engine light on.

CODE P0421. DEFINITION-CATALYST EFFICIENCY LOW-BANK 1. EXPLANATION-THE OXYGEN SENSORS MONITOR THE CATALYTIC CONVERTERS ABILITY TO STORE OXYGEN. PROBLEM CAUSES- 1. CATALYTIC CONVERTER DEFECTIVE (FAILURE POSSIBLY DUE TO #2,3, OR 4) 2. ENGINE MISFIRE OR RUNNING CONDITION. 3. LARGE VACCUM LEAK 4. ENGINE OIL LEAKAGE INTO EXHAUST-VALVE GUIDE SEALS, PISTON RINGS. THE PCM HAS DETERMINED THAT THE WARM UP CATALYST EFFICIENCY FOR BANK 1 IS BELOW TRESHOLD FOR THE CURRENT ENGINE OPERATING CONDITION. (BANK 1 IDENTIFIES THE LOCATION OF CYLINDER #1, WHILE BANK 2 IDENTIFIES THE CYLINDERS ON THE OPPOSITE BANK).

replace O2 sensors, or your Catalytic Converter.

I would suggest checking with dealer as most KIAs have a 100,000 mile warranty and catalytic converter as part of the emissions equipment should be covered.

Catalytic Converter is part of your exhaust friend..... You'll probably have to replace the converter entirely

Everything but the catalytic converter. I live in TN, the emissions test that I have to pass is a sniffer test. I have absolutely no emissions controls on my car, but when it comes time to pass emissions , i bolt the converter back on. Does fine.