need help code 481 and 145

A proper diagnostic check by a reputable service shop will be in your best interest. Throwing parts at a car per your friends' recommendations has only led to more problems.

Well your friend didn't know what a P0420 code was. It pays to ask the mechanic once they do the diagnostic test, to see why that code came up and if they can educate you on that code. Or when you get home, you can find it on the internet and go from there. What your friend told you, was absolutely WRONG. And even though you trust your friend, DO NOT trust them! In something like this, your friend does not know what these codes mean and why. What advice you got from him or her led you to your demise with your car and now your car will need a lot of money to be put into it. These codes refer to the catalytic converter as well as other codes. You have the following codes: P0070 - Ambient Temperature Sensor; P0145 (Sensor Circuit Low Response); and P0481 - Cooling Fan Control Circuit Malfunction. All of these have to do with the O2 sensor that you got replaced. And YOU, my friend, SHOULD NOT have replaced it yourself. You should have taken your car to a reputable mechanic to have the Check Engine Light code(s) to be read, and you would know for sure what problem(s) you have. Since you got the initial code of P0420, that is the "kiss of death" with a car or truck. That is the Catalytic Converter for sure. More than likely the converter you have in your vehicle is going bad or has failed altogether. Since you got the O2 sensor replaced yourself, and you are coming up with these other codes, that results from what you did to replace the sensor. My advice to you is to take your car to a place such as Midas, or NTB or some place that can do a FULL diagnostic for the Check Engine light. Tell them what you did, and how you got the initial code of P0420 and why your friend told you to replace the sensor when in fact the sensor was already good and didn't need to be replaced, but that it was the CONVERTER. Good luck to you and hope you get the correct answer you need for your vehicle. Please do not trust your friend on this again. They certainly do not know how to deal with cars at all.

2 choices here either educate your self as to how your vehicle works , and invest in a fault code scanner and some basic tools or take it into a known reliable shop ,taking advice from from someone who does not do mechanical work for a living has to be a no no !