I have replaced a sensor now 3 times. My car won't pass inspection and 7 engine codes come up.

po174
po431
po300
po022
po431
po300
po455

Can someone help?

 

It would have been helpful if you (a) took the trouble to edit your post to eliminate duplicated listing of trouble codes and put in the correct number of zeros, (b) specified what mileage you have on the car, whether manual or automatic, its maintenance history, and previous maintenance episodes, (c) what sensor(s) you replaced and under what circumstances, and finally, if your check engine light is on (which it should be).

For your info, here is what the codes (in numerical order) mean:
1. po0022 camshaft position; timing over retarded.
2. po0174 system mixture too lean.
3. po0300 random or multiple engine misfire.
4. po0431 warm up catalytic converter efficiency below spec.
5. po0455 emissions control evap loop gross leak

So now instead of 7 you have only 5 issues to deal with.
Start with the lowest first (po0022). Get your timing checked out, your toothed timing belt may have worn out and jumped a few teeth.
Next is po0174: check your air filter duct to the engine and all piping associated with intake vacuum. There's a good chance you have an intake air leak downstream of the MAF sensor located at the rear of the air filter box.
Now for po0300: random/multiple misfiring: well, if your engine timing is off and your mixture is too lean, that may very well be the cause. Otherwise, look for trouble with spark plugs or associated wiring.
Next in line is po0431, the catalytic converter. If your engine upstream is sick, (which it is), the fuel not being combusted properly will result in this code being set, so it may or may not be another red herring.
Finally po0455 indicates a big leak in your pollution control system. Check first that your gas tank cap is in good shape and is a proper Mazda cap and not a "universal" replacement. Then look on the underside of the hood and following the routing of the evap. loop plumbing described there until you find out where the leak is.

 

oldeng,
Both engines in the 6 series use timing chains, not belts. So that can't be the problem.

But I would ask, do you have the 2.3L 4-cyl, or the V6 under the hood?

 

OK, if the engine has a timing chain and not a belt, then the po0022 trouble code would most likely indicate a crankshaft angle sensor issue unless some prior maintenance work requiring removal of the timing gear resulted in subsequent incorrect re-assembly or set up.

 

If the timing was out a tooth the chain driven 4-cylinder engines dont start.

Hi everyone i work as a mazda technician in England , it sounds to me that the only fault code the technician should be following is p0045 there might be a fault with the Air / Fuel ratio sensor thats the first sensor in the down pipe before the catalytic convertor, inform whoever is working on the vehicle to disconnect that sensor then try the vehicle . Let me know what you find please.