Old way of car diagnostics without OBDII

OBDII ports didn’t exist on older cars. On older cars that don’t have а computer or sensors in the engine on the car, when you take them in for service you have to describe how the car is operating and what is not working. For the mechanic’s job to be easier he would ask you a lot of sub-questions. Because usually that isn’t out of a lot of help, the mechanic would use his skills to hear for any rattles in the engine, etc… So that he doesn’t need to take out the transmission if the fault is in the spark plug for example.

OBDII Diagnostics

There are various types of OBDII devices that you can get. Of course the more you pay the more you get. Their price range is from $4 to $500+. Here I will use a cheap one for $4 and it will describe on amateur level. While buying one make sure it supports the standards for your car. I would recommend buying OBDII v2, hence v1 can read bad information.


Connecting OBDII

All cars made after year 2004 have a OBDII connector (some cars before that year can have it as well). There will be a female OBDII port inside the car somewhere under the dashboard.

Place for connecting OBDII
Place for connecting


Because I am using the cheapest variant I need to download a program on my computer, or an app on my phone. There are a lot of free ones, so if one doesn’t work for you try another. There are a lot of ways to connect to your OBDII device, bluetooth, wifi, or cable. In my case I will be using bluetooth.


When you installed and ran the app, you need to turn on bluetooth. Choose pair with device and in most cases it will require a password, which is 0000 or 1234.

In the app choose which vehicle and engine you have. After setting up the app start the engine of your car and the app will track its usage. There is various of things you can read. You can even read a detection map where when a issue is detected it will show you where it is.

The scanner won’t precisely tell you what the issue is, but it will give you directions. When you see code P0301 that means that there was no ignition on cylinder 1. The scans are usually coded, but you can find out what a code means on the internet. You would fix issues by changing components and deleting damage history. If you run the scan again and that error doesn’t pop up anymore then you fixed the issue.

OBDII Scan Issues

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