Multiple Fault Codes

codes 141 and 140 are Os sensor, but may be caused by 440 code which is an evaporator problem so will need to be smoke tested. also 303 is a misfire which are very hard to diagnose and should be left to professionals for cheapest route. you can check for vacuum leak and compression to knock that out, but other than that it should have a professional freeze frame it. 341 is a camshaft sensor problem which can be where wires run to close to plug wires and or shorted or sludge buildup so it cannot read correctly. All of these can be a bad pcm as well, but have it looked at first prior to changing or replacing parts. If this vehicle has been in a flood then normally they are scrapped as water damages the modules.

Thank you. Your answer is greatly appreciated. The car has not been in a flood. It just did not pass the emissions part of the yearly inspection, and I have to fix it to renew my registration. It is a Texas thing. I wont be doing any of this work myself. I just cannot pay for everything to be done at once, so I have to plan how to approach it all with the mechanics.

Anyway, if I am reading your answer right, I should start by having the PCM looked at and possibly replaced. If it isn't the PCM, then check the camshaft sensor and wires, then check the spark plugs and wires. The O2 sensor or evaporator problem. is a separate issue and maybe can wait until the other things are resolved? If I have misunderstood, please let me know. Thanks again!

well when you see the mechanic he will try to fix the U code first as that may take some of the other codes away. I do not think it is the pcm they can be rebuilt anyhow so they are cheaper.if O2 and evaporator are still messed up you will not pass inspection they both need to be fixed, but wait until your mechanic says.