How to Reset Volvo 240 check engine light?

Answer 1

For a 1993 Volvo 240 DL refer to the On Board Diagnostic under the hood:

There is a small black box under the hood on the left fender well (driver side) near the hood spring. This box has a cover on it with a probe in a holder. Remove the probe from the cover and put it into hole #2. Turn the key on.

There is a button in that black box that needs to be pressed for a second or two then let up. A red light will start flashing a code. write this down. The flashes will be something like 1-2-1 or 2-3-1 or what ever. After it's done push the button again and record the next code. If it's the same code as the first this means there is only one code. If it's different then you must push the button again and record the code. do this until you get back to the first code.

Now you should know what the first and last codes are. Now start the process again. this time after you read the last code, hold the button down for at least 10 seconds and wait for the light to come on and then push it once again when the light is on, for a second or two. you should be done.

To check it you can once again start the process, if you get 1-1-1 it's cleared. Start the car and the Check Engine Light should be off.