So here you are in California or any other state that requires a smog check certificate every one or two years in order to renew your registration. You take your car into a smog check shop and it doesn’t qualify to take the test because the “check engine light” on your dashboard is illuminated but your car seems to run fine. Now what?
Well, unless you have an honest family member who is a mechanic clearing this light so your car is able to take the smog check test could get expensive.
First, you need to determine what code or codes is stored in our car’s computer. You either need to purchase or borrow an On Board Diagnostics (odb-ii) code reader and plug this into your car’s serial port interface and download the error code(s).
Since code readers cost between $99 and $400 you might want to go to an auto parts store which lets you borrow their code reader. Autozone and Pepboys both will let you borrow one as long as you leave some sort of collateral at the front desk.
So after you plug in the code reader and hit the “link” button the code reader will come back and give a listing of error codes stored in your car’s computer. Make sure to write these down so you can look them up later on the Internet or ask the person at the part’s store what part needs to be replaced.
For example, the code reader comes back with P0136 as the error code stored in your car’s databank. You can enter that same code into Google or and odb-ii trouble code site such as odb-codes.com. In this example the problem would be a faulty oxygen sensor in your exhaust system. You even know which one it is too. Bank 1, Sensor 2 which is the oxygen sensor on the passenger’s side after the catalytic converter.
You can probably pick up the part from the parts store where you borrowed the code reader for $30 to $99. This is a simple fix as you simply unscrew the faulty o2 sensor and screw in the new one. Now you have two choices: 1) clear the code with a code reader or 2) drive the car until the check engine light turns off indicating when the car is able to plug into the smog computer and take the test.
If you choose option 2 then you must drive the car about 60 miles or so in total so that your car’s computer cycles through and automatically clears the error code.
Once the check engine light is turned off from your car’s computer you are ready for your smog check and you saved yourself at least $200 in “labor”.
Be sure to look for smog check coupons as almost every shop advertises them and you can save $20 or $30 off the test. Good luck!