98 s420 - OBD II scanner unable to pull codes
 

Hi...My OBD II scanner is unable to read codes from the OBD port on my 98 -420 -w140. There is NO CEL. The car drives fine and i have used this scanner to pull codes from this car in the past with no issues. The car is due for inspection and i routinely scan the OBD port before i take to the inspection place.

I connected the scanner to my 03 ML500 and it works fine. Looks like the scanner is not the culprit here.

I checked the fuses inside the main fuse box and all the fuses are fine. Is there a fuse for the OBD port somewhere else in the car ??? Please help.

Thanks

your 98 has a very early version of obd2 so you may not be able to read live data with your scanner as that part of the programming may still be propitiatory. If there's no CEL. Your car will pass inspection.

Hi Al......Thanks for your reponse but i am not sure i explained the problem correctly.

The OBD2 scanner says 'READ FAILED. Unable to read data from vehicle. Please make sure KEY is on and tool is connected to vehicle.'

The scanner is properly connected and the engine is running. I have used this scanner on this vehicle several times in the past 8 years & never had a problem. I hooked it up to my 03 ml500 and it works fine.

So when i take the car for inspection i am going to have the same problem. Looks a fuse is blown somewhere which is knocking off power to the OBD2 port under the steering wheel. But i don't know which fuse that is. Thanks in advance for your suggestions

smk_texas

Odd, I don't see a fuse for the diagnostic system.

http://www.mbcluster.com/Products_Fu...ation_W140.jpg

I have a couple of OBDII readers, the one that never fails to work is my CP9125 which is basic and lives in the center console of my 97 E420. If you're in Dallas, we can try mine, or use the 38 pin connector under the hood with my carsoft 7.4 multiplexer.

Thanks Al. I appreciate your offer. I am going to take it to the inspection shop on Friday and see what happens. Will keep you posted. I am thinking mostly like the diagnostic module but don't know for sure.

smk_texas

data port is under the hood

Do you know exactly where under the hood ???? Thanks very much.

smk_texas

the passenger side fender,its a round cap that screws off.you need a special data connector.you can only acess a few info under the dash.Thats why any performance chips that attach to it don't do nothing,just a waste of money

Hi ...Thanks for the help. I took the car for inspection and it passed. They were able to connect to the port and read with no issues. It looks like my scanner is faulty. Thanks again for the suggestions & guidance.

Best Regards
smk_texas