Rover pre-2001 OBD socket

[Rob Bell]

I've not ever seen this posted on the internet before, so thought I'd post what I've been researching (which has been prompted by Phil's efforts to reverse engineer a fault-code reader for all of the MGF's ECUs )

The socket, as you all know, is the standard OBD socket - as found on any car that is OBD-II or EOBD compliant (EOBD being the european version of OBD-II)

The socket pin scheme is shown below:



The socket pin out shown is the standard OBD pin-out. The pre-2001 Rover version is pretty similar, but has a couple of extra pins populated, and one deleted.

From researching the electrical wiring diagrams for the Mk1 MGF, the pins are (letters in parenthesis are the wire colour codes):
1 - (YK) Alarm/ (K) EPAS ECU data
2 - Unused
3 - (RU) Alarm ECU data
4 - (B) Earth to header 808
5 - Unused
6 - Unused
7 - (K) MEMS, ABS ECU data
8 - Unused
9 - Unused
10 - Unused
11 - Unused
12 - Unused
13 - (YK) Airbag ECU data
14 - Unused
15 - wiring diagrams claim that this is for battery power via passenger compartment fusebox, fuse 12 (15amp) - but I believe this to be incorrect because...
16 - the wired pin is in fact pin 16 - which would be consistent with later OBD standards.

The omitted pin from the standard OBD pin out is pin 5, which is usually used as a signal ground. This can cause problems with certain types of diagnostic equipment which may use this pin for a ground.

The extra pins are pins 1, 3 and 13 for the EPAS, Alarm and Airbag diagnostic data.

The electronic protocols used are well beyond my basic electronic knowledge, but perhaps this may be of use to someone

[Rob Bell]

A couple of pictures of the MGF OBD socket - note that it is inverted compared to the diagram shown above.

[jonaf]

I was lucky to come across a T4 which I bought for what I think is a fair price. The screen on the PC does not work properly (it closes down after a few seconds, which I believe may be just the screen hinge contact being faulty) but it works OK with an external screen connected. The hand held unit seems to be OK.
Now I am going to learn how to operate the thing. It came with four diagnostic cables with different contacts. Which one should I use with my '96 MGF? The blue DTC0061A, the red DTC0065A, the yellow DTC00060A or the grey DTC0064A?

[Rob Bell]

The Red and yellow don't look to have the correct pin positions, but the other two I can't make out. Plug them in and see which can establish communication with the ECU?

[jonaf]

I made an attempt to carry out a faults scan and the T4 advised me to use the DTC0061A cable with the blue connector. However, I did not get the proper DTC0007A extension cable which connects to the serial connection box DTC0006A so now I am stuck...

[Rob Bell]

Ah - that's a problem

Is it worth approaching the manufacturer of the equipment (which is still in existance!) a telephone call to see whether they'd supply a replacement for the missing cable?

It may be possible to make your own up - but how the sockets are wired up is anyone's guess Nothing on googling the internet I take it?

[jonaf]

Ah - that's a problem

Is it worth approaching the manufacturer of the equipment (which is still in existance!) a telephone call to see whether they'd supply a replacement for the missing cable?
It may be possible to make your own up - but how the sockets are wired up is anyone's guess Nothing on googling the internet I take it?

I got the rest of the cables from the seller and I have attempted to make a make a fault code reading. Unfortunately the T4 can't establish connection with the ECU

[Rob Bell]

Check simple things first: dirty connector, broken wire etc etc

Perhaps worth a chat with someone who uses a T4 regularly? Nick of Austin garages might be able to offer some advice?

[jonaf]

All the obvious things have been checked. The contacts look fine and I could not find any broken wires in the connectors.
I Norway it is very hard to find anybody who knows the T4. How do I get into contact with Nick at Austin garages?

[Keith Williams]

All the obvious things have been checked. The contacts look fine and I could not find any broken wires in the connectors.
I Norway it is very hard to find anybody who knows the T4. How do I get into contact with Nick at Austin garages?

Nick's username on here is austingarages . You can PM or email him via that name.

[Rob Bell]

As Keith says Jon.

BTW, what happens if you press "MORE DETAIL"?

[jonaf]

When I try to carry out a file integrity test I get this message:

[MaddAussie]

What are the serial port settings on the laptop? I remember talking to Mark from Z&F and he said that TEST BOOK was very picky on serial port settings.

[jonaf]

I have not changed any settings so I can't see how this should be a problem. I do not know how to change them, anyway.

[Rob Bell]

"File system integrity failed" looks to be a rather scary message. No idea what it means here - after all, the hard disc appears functional if it has loaded the T4 application?

Other enthusiast T4 experts are around - usually to be found on the Rover 75 and MG ZT club forum: having a T4 with these cars is invaluable for switching functions etc on the BMW-designed CAN-bus system. If Nick can't help you, it's worth heading over there and tracking them down. Unfortunately at the moment it seems you have a rather expensive paper weight

[jonaf]

I get a message that tells me I am using the incorrect diagnostic lead. But I have indeed connected the blue DTC0061A, so then it may be something wrong with it? Can't find any broken leads, though, and the connectors look fine.

[Rob Bell]

Is there electrical continuity between each socket? Trouble is I don't know how these leads are wired?

[jonaf]

Is there electrical continuity between each socket? Trouble is I don't know how these leads are wired?

All connectors have been opened and examined. Perfect connection between all contacts.
First of all I need to have the file system sorted, I think.

[Rob Bell]

Back everything up and I agree with you: get the file system sorted (retort at or replacement HD?)

[austingarages]

I made an attempt to carry out a faults scan and the T4 advised me to use the DTC0061A cable with the blue connector. However, I did not get the proper DTC0007A extension cable which connects to the serial connection box DTC0006A so now I am stuck...

The T4 diagnostic program is handed down from the original Testbook 1,2 and 3 days - the cable connection procedure was not updated on the screen!
T4 main long diagnostic cable is DTC 4007B and does not use the serial connection box DTC0006A. The blue diagnostic connector plugs straight into DTC4007B.