i am the owner of 6/1992 2.6 litre TR Magna
that has a dead TCU, its been probed and has no output, stuck in third gear.
i am looking for a replacement TCU MD750103 or equivalent and am wondering if there is any procedure in initializing the replacement unit?

regards, Steve

With these cars the part number is not all that important, the main thing you need to determine is if your car has a 2 plug or a 3 plug TCU, if it is a 2 plug TCU (most common) we do have these listed in our ebay store, if 3 plug then that will be difficult to get

The TCU from both the 3.0 and the 2.6 can be used

thanks for the reply.
so it does not matter that the TCU is out of v6 motorcar?
mine is the 3 piug unit.

If yours is a 3 plug unit still does not matter if comes from a 4cyl or V6 but will be difficult to find this particular unit

Hi Lotto, I'm currently wrecking a 92 4cyl auto magna atm, where abouts is the tcu located as I might be able to help you out with the part

Subject to the unit being designed with logic gates and NOT microprocessors, it could probably be repaired. Most of the service manual stuff would treat the thing as a sub assembly so its a bit hard for me to say exactly whats what.
Maybe the 3 plug type could be changed for a 2 plug type.
Nothing is impossible
Hope this gives some hope

As a follow up to post #6, I looked at the manual to compare the variants.
91/93 4 cyl cars seem to have the 3 plug version. In the manual, drawings 54-3D-49 and 55 appear to be wrong in that the 'INHIBITOR connections are shown numbered as 51 to 58 but they should be (?) 31 to 38; or at least they are inconsistent with page 23-2-14 of the manual.
Having gone through what I can see, it is my view even more strongly than before, that the 2 plug version could be used by changing the plugs and re-terminating the wires.

2 plug with ECS 3 plug no ECS


Pin # function pin # function Pin # function Pin # function


Comments:
Different people use different terms for the same thing. Even the same person can be variable in the use of some terms.
Eg; 1. Ground and earth are the same thing from the general point of view.
2. ‘power’ and ‘power supply’ and power supply backup mean the 12 volt supply, but might be coming from different parts of the battery supply system.
However, many of the functional inputs and outputs are identical; Inhibit switches and pulse generators.
The ‘Diagnosis’ connections need to be checked just to ensure they are the same. Generally, the data sources inside the TCU will be functionally identical.

What the difference is between ECS and NO ECS is not clear to rumpfy but this appears to be the reason for the 2 plug and 3 plug variant. It would appear that the mechanical cutouts in the TCU for the connectors is identical so it may be possible to change the 3 plugs for 2 plugs and rewire the connections inside the TCU.


Hope this helps.

ps there is a table which I'll post next if I can work out how to do it!!.