240DL 1993 check engine light

jwilt5 · Post by **jwilt5** » 19 Jun 2009, 08:50

I have checked the code for my check engine light and it is telling me the problem is with the Mass Air Flow Sensor. This had been replaced in 2006 and there has only been 20,000 miles put on the car since then. I had recently replaced the air filter and noticed that the filter housing was pushed in at the side and squeezing the edge of the air filter out. I thought maybe that might be the problem that it was not sealing correctly so I used a heat gun to heat up the edge and straighten it out enough to put the filter in and seal it properly. But I still have the check engine light. The car is running fine and starts with no problems, which the manual states would also be an issue if the Mass Air Flow Sensor was defective. I am wondering how to reset the check engine light so I can see if the light comes back on again since I corrected the seal of the air filter.

Post by **billofdurham** » 19 Jun 2009, 11:26

Welcome to Matthew's Volvo Site.

The codes are cleared using the diagnostic unit in the engine compartment.

240 DTC clearing.pdf: (109.89 KiB) Downloaded 900 times

Bill.

jwilt5 · Post by **jwilt5** » 19 Jun 2009, 11:43

Thank you!! The code clearing worked and the check engine light has still not come back on. Maybe I actually fixed it and saved $$$.

Post by **billofdurham** » 19 Jun 2009, 12:31

You are welcome. Thank you for the update.

Bill.

woodstockCT · Post by **woodstockCT** » 27 Jan 2013, 15:26

billofdurham wrote:Welcome to Matthew's Volvo Site.

The codes are cleared using the diagnostic unit in the engine compartment.

Can you tell me exactly where that would be located? Having the same problem with trying to reset my Check Engine Light and I also checked behind the cluster panel for a switch and could not find one. Is the Diagnostic Unit the only solution?

woodstockCT · Post by **woodstockCT** » 27 Jan 2013, 17:55

Found it and reset the codes as follows for those who still need help:

There is a small black box under the hood on the left fender well. 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.

Post by **billofdurham** » 28 Jan 2013, 11:26

Thank you for the update.

Instructions for using the OBD are pinned at the top of the forum.

Bill.