Not being able to read those codes easily is of itself a pain in the but. But the operative word is EASILY!
The early computer logic of the cars generally had a means to let the owner read the codes out by diddling with the ignition key and then flashing a check engine light. I guess I do not know for sure how universal that was which means if all cars did the same thing exactly or not nor for sure how new they had to be before diddling did not read codes out that way but generally it was to take the ignition key and start with the key off and then Turn the key to on, then off, then on, then off again and then ON and leave it there and the check engine light would then start blinking. You count the blinks. The first blink sequence or grouping was a standard number and then it read out a series of two digit codes and then there was a finishing number.
It was both bothersome to do this and a bit of a problem counting the blinking light so I usually repeat this a few times until the sequence makes sense to me.
Are they all the codes? No, it is the ones accessible using this method. There are others,.
If your mechanic erased them, it makes no difference, codes are stored generally through the first 50 key starts and then they go by the first in last out approach.
How easy is it to use? You need a chart to tell what a two digit code means.
Which brings up where do you get a chart. There might be one on the internet some where.
I have service books for cars I own. Some of them are factory manuals because I restore them, some are Chilton, motors, Haynes or Mitchels manuals which are abbreviated versions. They cost about $25.00 or so or you can find them at swap meets. Why do I have them. Because the first time I use them they generally save me the money I spent to buy them by giving me enough information so I don't **** money away buying parts I don't need to fix a problem that I am clueless of and thus just throwing parts at it hoping something fixes it.
The day has long since past that being a decent shade tree mechanic and some experience a piece of wire and some chewing gum are all you need to fix something with.
You need to be able to read and have something to read to take care of business.
No, I do not own a scan tool. Yet. But at about $200.00 they are becoming cost effective to add to my tool box.
Or you can go to some where like
Checkers, O'Rielly's, Autozone and others and they will offer a free scan read out. Why? Because it leads to buying parts from them.
What is the best parts house to go to?
Dunno, probably the one closest to you.
I like CarQuest and Napa as being the best. An O'Rielly's is close to me. I have yet to purchase parts that are bad in general from any of them although PepBoys seem to be the most expensive so I don't go there.
The local O'Rielly's puts up with me, makes me laugh and will special order things I want. The CarQuest seems to have the best computer oriented parts books and the most automotive oriented counter help. Napa has the best deep parts stock for out of production automobiles but CarQuest can find parts numbers the best.
Dunno which one, but I rarely buy parts on line and when I do I have had good luck with "Rock Auto"
Dealers? Have their place but usually for something very specific that can be only be obtained at one. Unless of course the car is out of production and the dealer no longer exists.
So use the one best for you and figure out how to get the codes read and it would help you to buy a DIY Fix it book for your car.
Or?
Have real deep pockets so you can pay some one else.

 

I am new to this forum,and i have to agree,Get the codes read,go to autozone they do it for free.A coolant temp sensor will always tell the brain that the engine is cold and give extra gas to warm it up even tho its not cold, crank postioning sensor will do the same,Alot of problems can occur>First thing you need to do if you dont have a obd2 reader is just take it to autozone or advanced auto.