The OBD is the Onboard Diagnostic Computer that monitors the CEC's, (computerized emission controls) of which your vehicle has many, such as the AFS, cat, evap,O2 etc,etc

If any of these have operated outside of the parameters set in the computer that would cause the vehicle to exceed 1 1/2 times the federal emissions standards it sets a hard code,ie. MIL light, if they operate outside of the range for a brief time, it stores a soft code.

However, the intent and purpose of the OBD computer is to eliminate guesswork as to why a vehicle has running problems.

All the advice given in the above posts, if indeed any of them are the problem, would be stored in the computer and would generate a code that is retrievable witha scan tool. This tells a person for instance, if the O2 sensor is malfunctioning, even for a brief period.

The DLC, ( diagnostic connector link) I believe is located on the right rear side of the firewall inside the engine compartment, it is a plastic narrow rectangular fiting about 2 inches long and 1/2 in. thick with 16 pins in it.

But, a special scan tool is needed to connect and read the codes. Some auto supply stores ( autozone) will scan the OBD for a small fee. A good web site is www.obdii.com for explanations and advice.

Good luck

Absolutely great explenation.
The diagnostic connector I belive is under the steering wheel (it looks like it).
At different times I connected and disconnected air mas flow sensor, and other sensors, also tried to start the car with the blown fuse in the black box close to right fender and after replacing it. Tried disconnecting the battery. the rearview mirror was disconnected.
Is it possible to clear the codes on my own without the special tool or it must be connected to the special tool.?

Thanks

can you please tell me if this tool will read the codes in my car and help me fix it.?
The link is here http://www.actron.com/cgi-bin/web_store.cgi?page=cp9135.htm&cart_id=8040161_12887

Whether or not you can clear the codes is kinda a trick question, one can clear certain codes after 3 drive cycles IF the problem goes away and the malfunctioning part operates correctly, other codes will not clear until after 40 drive cycles, However, on some US model vehicles, ( I am uncertain about MB) if you disconnect the battery for 5-10 minutes, the code will clear, but the monitors will be at 'not ready' for a length of time, this is only a problem if you are in an area that has OBD emissions testing like here in St Louis, the festering, oozing ulcer on the otherwise beautiful state of Missouri.

That scan tool sounds like it will work, the thing with it is that it reads onlly generic codes like P0101, MB may have some manufacturer specific codes (I am not certain about this), like P1456, some scanners are manufacturer specific.OBD was implemented in 96, so a push was made to have all vehicle manufacturers use the same codes, this is the case in newer models from about 99 on, but alot of 96-98's still will have a few Manufacturer codes.

Hope this helps, another good web site is www.necvecs.com, I think thats the right address, damn, its early and I have only had 1 cup of coffee, can't think, must have caffeine and nicotine, the breakfast of champions...


Really, a scan tool is invaluable for 96 and newer cars. Takes alot of guess work out, they will not exactly ID a problem in most cases, but will point one in the right direction.

Hi

I tried the link but it does not work, please check for the right
one for me.
Thanks

Umm, how about supporting this site by getting one of these: Ottoscan

__________________
Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
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I sounds and looks great but the other scanner is approx $100 which is about 25% of the one you are suggesting.

Thanks

www.ncvecs.colostate.edu is the correct web address. This is the national center for the study of auto emissions and they have a pretty good web site with a forum.

Thanks for the correct address

I got my codes for my 97 e320 , it just came up with one code p0100.
It looks like the mas sensor , from the list of codes , please confirm .
Is it possible to check that sensor if it is good or bad or can it be fixed somehow?

Thank you

Yes that is correct, either the unit itself or the circuit. There is a way to test voltage on it that tells if it's working or not, I believe it should read around 4-5 volts, you shoold confirm this as i am not certain.

You might begin by checkning the connection to it, clean it etc.

Good luck.

I have it removed, and would like to know if it could be tested on test bench and also if it could be repaired?

Thanks

i would like to jump in here.
i have a similar problem where car is running but wont "go" when accelerating hard. it is worse when cold. NO CHECK ENGINE LIGHT.
i have spoken to different shops and they all say no " light -no codes " .i am sure it is the mas. how do i check it?
there was mention of " soft codes" . are they still there after batt. has been disconnected?

QUESTIONS? QUESTIONS?

Any ideas?