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HC is raw or un burnt fuel. CO is incomplete combustion meaning the air fuel is burnt but not burnt completely. check O2 sensors for operation, fuel pressure, gas in oil or how long has it been since an oil change. check engine timing, dirty injectors. when was the last time a tune-up was done plug/wire condition is the air filter clean. just some things to check
No. If you have failed your emission test, they should have told you why it failed. If not, replace the oxygen sensor (O2 sensor); some makes/models have two - so find out when you go to the auto parts store.
Also, as a tip, make sure you have driven your car a good distance before going through to be tested. If the engine is not at "operating temperature" it will not read on their machines correcty.
Please let me know if you need further assistance.
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P0031 Oxagen senser heater circuit. The heater circuit can be checked with a test light connected to ground. ( a tast light is an ice pick looking tool with a clear handle with a 12 volt bulb inside and a ware with a clip to connect to grond, the light will light as the tip is touched to anything powered up with 12 volts and sometimes a little more and a wholde lot less) Find the oxagen sensers ( thier screwed into the exhaust pipes) Disconnect the electrial connectors and connect the test light to ground, with the key on test the wires in the plug connect ed the vehical. one of them should light the light, if it does reconect it and test the rest of the sensers, recalling which wire was live. ( most are white or grey but they vary some. If all the sensers have power it's not the power but the senser failed. with an ohm meter test the senser for the wire that was hot to the other wire that is the same color if the sneser is open ( no circuit ) you have found the bad senser. If you can't find power going to any of the sensers. Check the fuse boxes for blown fuses ( check them all with a test light) If you find a blown fuse replace it but go back to the wiring tjat connects to the sensers and you'll find someplace where the wire melted to the exhaust pipes and shorted out, blowing the fuse. The sensers short out too but not very often.
Don't know if this will answer it. O2 sensors send info to the computer to make adjustments to the emissions system. Over time the O2 sensors fail which cause the computer to light the "Check engine" light. Originally the "Check engine" light was dedicated to an emission system fault. Now manufactures use it for a variety of abnormalities. To know what the "check engine" light means you have to either take it to a mechanic or buy a OBDII scanner (around $100) and read the code yourself. I like to read my own codes. These scanners are good for all modern cars. Instructions are included EZ to follow.
Long story short, don't worry about it the check engine light will come on when O2 sensor fails. Happy motoring!
I've always found the following to help with emissions tests on older cars:
Check & replace air cleaner if dirty (difficult to see light through it),
Check spark plugs ( will also be good indicator of any bad cylinder so keep them in order of removal) - if any look/measure bad, replace the set.
Check engine oil quality & replace if dirty (or you can't remember the last time it was changed). Dirty oil = higher emissions.
Run engine on higher grade fuel for a few days and during test (better fuel = lower emissions).
If o2 sensor is the problem it will set off codes.
If you are in Texas, that car is EXEMPT from emissions. The Volvo onboard OBC II computer does NOT communicate with the machines that test for emissions. It will NEVER pass. You can spend thousands on that car and it will never pass due to the computer issue.
O2 senser usually fail.
anything else fail??? did the inspectionstation tell you what need to be done to pass.??
do you have the print out of the inspection????
any machanic should be able to fix what ever the problem is.