obd 1 or obd 2 or eobd?

[mercjim]

i've got a bit muddled alate with this sort of technology....
my friend as an obd tester / meter and i bought the 38 pin to obd 2 lead to fit his meter...
when we connect to the car via his laptop, i turn on the ignition and nothing... the program says not connected to a vehicle....

can anyone tell me which OBD my 1995 mercedes c200 elegance is please? it as the 38 pin round datalink socket right in front of the ECU, in the module compartment in the top right of the engine bay, as you look from the front of the car that is.

thx all in advance
jim

 

[richard]

Hi

Its none of them !

OBD-II / EOBD are presented on a standardised diagnostic socket above drivers feet on a Mercedes.

When OBD-II first got mandated in the USA (from 1996), Mercedes made a little converter box which interfaced between the OBD-II socket ("SAE J1962 connector") and the engine management system (which also is connected to the 38 pin socket) so as to comply with the USA requirements.
Europe then changed the OBD-II spec slightly (for no obvious reason) and made EOBD, and then we started to get the "standard socket" on all euro cars also. Of course we only took 5 years do catch up and probably wasted large amounts of cash doing so, and EOBD only became mandatory in 2001. (cynic, sorry)

EOBD/OBD-II only cover the emissions related systems, which is engine management system and sometimes transmission systems.

So, given the age of your vehicle it almost certainly has some "private" diagnostic protocol between the engine management system and the "Hand Held Tester (HHT)" - which was the pre-runner to Star Diagnosis.

Cheers

Richard

 

[stevesey]

Mine does OBDII (ECU only) on pin 4 of the 38 pin socket - which is not the PIN that most of the 38 pin MB -> 16 PIN OBDII adaptors on ebay wire up to (pin 15).

Try buzzing the adaptor through with a meter or opening it up and checking might be worth a try.

 

[richard]

Definitely worth a try, it is perfectly possible that the older ecu's support some of the OBD-II - enough to get some diagnosis. I just think 1994 is a bit too far before OBD-II came about to have it in the ECU. By 1998 its highly likely it did have some support in there.

R

 

[mercjim]

mmmm, so the obd connector is actually above the drivers foot well cover? or am i wrong....
i honestly thought it was the big 38 pin socket right in front of the ecu....
which is the lead i got to connect to it thru ebay when i asked for the specific make and model of car....
seems 1995 was a bitch of a year for my model of car... when i go to get spares... im asked what year? when i say 95, they ask what make of part is it? i say genuine mercedes... they say... cant be, such n such only made them.... or... no parts listed... even at mercedes lol.

 

[kth286]

mmmm, so the obd connector is actually above the drivers foot well cover? or am i wrong....
i honestly thought it was the big 38 pin socket right in front of the ecu....
which is the lead i got to connect to it thru ebay when i asked for the specific make and model of car....
seems 1995 was a bitch of a year for my model of car... when i go to get spares... im asked what year? when i say 95, they ask what make of part is it? i say genuine mercedes... they say... cant be, such n such only made them.... or... no parts listed... even at mercedes lol.

Your 38 pin facility will give you simple 2 digit flash codes.

You just need a simple LED tester and the read off chart for PMS (Siemens) system.

When at the dealer, you only need to give the full VIN - everything else will follow on automatically when he inputs that VIN into computer.

 

[mercjim]

we seem to have got crossed wires...
my friend as an obdII unit that connects to his laptop, the software he is running, when the obdII unit is connected to my 38 pin lead, which in turn is connected to my car which is a 38 pin receiver for the male connector isnt even connecting to my car.
ignition on, he boots up the software after connecting to the connector next to ECU and says "no vehicle connected"
havent tried the 1 under the drivers footwell yet, not sure if its gonna be the same connector, or just the obdII connector that connects in to the 38 pin 1 i bought from ebay.
it wont be going to mercedes for the diagnostic as im not willing to pay £97.50 + vat for 1 hours labour to do it as its a 5 minute job. just my friend, his obdII unit and the software.....

 

[stevesey]

what khh286 is saying is that some of the earlier cars (without ODBII) can be interrogated using a simple circuit (LED+resistor I think) plugged into the 38 pin socket - here a link with some info (this link also for help on which pins to connect to).

Otherwise you might want to try opening up your 38 pin adaptor and re-wiring the lead that is probably connected to pin 15 to pin 4 and then having a go - if this doesn't work the blink method is your only choice.