3PIN diagram to OBDII diagram

[StripesSA]

Hi Guys.

Just want to find out something.
I want to convert my wife's car's 3PIN diagnostic port to the OBDII style, but don't want to buy the converter as I have access to a breakers yard with vehicles where the OBDII ports are left in the vehicles with enough wires to spare.

So the first question is:: What pin number on the 3PIN goes to what number on the OBDII, and which OBDII pin numbers get positive and negative?
This will be a hard wired conversion, IE, permanent and the 3PIN will be cut off.

Reason for the trouble is, no garage in my area has the 3PIN-OBDII converter cable and I have to supply it, and the chances of it going missing is good.

Second question:: can a generic OBDII-USB cable be used with any of the Fiat ECU scan tools, or must it be the VAGCOM KKL cable? I have access to a generic style, but don't know if it will work.

For interest sake, it is a 2000 Fiat Palio 1.2 MPi 8V(South African Spec)

 

[varesecrazy]

Hi Guys.

Just want to find out something.
I want to convert my wife's car's 3PIN diagnostic port to the OBDII style, but don't want to buy the converter as I have access to a breakers yard with vehicles where the OBDII ports are left in the vehicles with enough wires to spare.

So the first question is:: What pin number on the 3PIN goes to what number on the OBDII, and which OBDII pin numbers get positive and negative?
This will be a hard wired conversion, IE, permanent and the 3PIN will be cut off.

Reason for the trouble is, no garage in my area has the 3PIN-OBDII converter cable and I have to supply it, and the chances of it going missing is good.

Second question:: can a generic OBDII-USB cable be used with any of the Fiat ECU scan tools, or must it be the VAGCOM KKL cable? I have access to a generic style, but don't know if it will work.

For interest sake, it is a 2000 Fiat Palio 1.2 MPi 8V(South African Spec)

Pretty indepth..

Personally
I would ask on the multiecuscan forum..

But maybe s130 . Or g8rpi

Have some info.


Copy chinese cables are ok in both elm and kkl.. the switchabe are a little more hit and miss. Charlie

 

[g8rpi]

Pretty indepth..

Personally
I would ask on the multiecuscan forum..

But maybe @s130 . Or @g8rpi

Have some info.


Copy chinese cables are ok in both elm and kkl.. the switchabe are a little more hit and miss. Charlie

Hi,
@StripesSA
Fairly straight forward job. You will need a old OBD connector an bracket. The only connections you need are

Chassis (0v, can be from center pin of existing plug) to pin 4 of the OBD
"K" (left hand pin)from existing plug to pin 7 of the OBD
"L" (right hand pin)from existing plug .
+ 12V, fused (you will have to find this, mybe radio supply) to pin 16 of the OBD. See picture below.
fiat 3 pin.jpg
Note this will only work with a "dumb" KL interface, a ELM 327 won't work properly.

HTH,
Robert G8RPI.

 

[s130]

You beat me to it Robert. Must be those two huge side-pod engines of yours

 

[g8rpi]

That car hasn't run for nearly twenty years. I still have the laptop I used for diagnostics and data download on it though. The wife says I'm a horder

 

[varesecrazy]

thanks chaps...!!:worship:

 

[StripesSA]

Hi Guys

Thanks allot. Especially FOR that diagram. Yes I can get hold of the whole thing, bracket and wiring etc.

Just another question, according to you all, there is supposed to be 3 wires in the 3PIN, but mine only has 2?

Viewed from the front it looks like I only have "GND" and "K".

Why is this?

And then, what is the maximum length the new plug wiring lengths can be. I want to move the plug into the cab.

Thanks in advance

 

[g8rpi]

Hi,
The interface stndard is ISO 9141-2. This uses one or two data lines caled K and L. The K line is bi-directional so can only talk or listen at any moment in time. The L line is unidirectional so only transmits data. The L line is optional and is not always connected. It appears your car does not use it, so don't connect to pin 15 of the OBDII connector.

Robert G8RPI.

 

[StripesSA]

Hi,
The interface stndard is ISO 9141-2. This uses one or two data lines caled K and L. The K line is bi-directional so can only talk or listen at any moment in time. The L line is unidirectional so only transmits data. The L line is optional and is not always connected. It appears your car does not use it, so don't connect to pin 15 of the OBDII connector.

Robert G8RPI.

HI Robert

Thanks allot. Explains why there is only two wires.
Just asking again about the generic OBDII diagnostic cable, will it work or do I need the VAGCOM KKL?

 

[g8rpi]

HI Robert

Thanks allot. Explains why there is only two wires.
Just asking again about the generic OBDII diagnostic cable, will it work or do I need the VAGCOM KKL?

Hi,
The Fiat 3 pin interface will only work properly with a dumb K-line interface such as the VAG-COM compatible KKL to USB. This is because Fiat use additional signalling that does not fully conform to the ISO standard. A smart interface like a ELM-327 only recognises the standard messages and can't be reprogrammed by the software on the PC. The dumb interfaces are completely controlled by the PC software so can be made to work with non-standard signalling and messages.


Robert G8RPI.

 

[StripesSA]

Hi Guys

Got an OBDII connector from a banged up Ford Focus today.
Will start removing all the pins and only connecting the ones needed. Will be using the same colour codes as my 3PIN.

Just another question.
Robert mentioned that the +12v needs to be fused, what should the minimum rating be and the maximum?

Photos and a write up may follow...

 

[g8rpi]

Hi Guys

Got an OBDII connector from a banged up Ford Focus today.
Will start removing all the pins and only connecting the ones needed. Will be using the same colour codes as my 3PIN.

Just another question.
Robert mentioned that the +12v needs to be fused, what should the minimum rating be and the maximum?

Photos and a write up may follow...

Hi,
It just powers the interface so minimum size is not an issue. It's there to protect the wiring so should not be larger then the rating of the cable used. 1A should be fine.

Robert G8RPI.