Disco 2 Manual/Tiptronic gearbox

Stanleysteamer said:

Thanks very much for this.
i'll read it tomoz cos I am sh!t at understanding maths, physics etc in the evenings. My brain just doesn't work well.
but I am grateful ever so much for you having bothered to try to explain this stuff to me.
But just ojne thing before I sleep on all, this.
TCU? Is that what most of us call the BCU? and is it the triangular thing under the passenger seat?
Cos altho i have taken the ECM out loads of times I have never touched the BCU.
Sorry to ask such a basic question.
The rest of it seems to be simply a question of wiring like wot I am used to, relays etc.
Once again, thanks.
Stan

Click to expand...

DrecklyD2 said:

TCU transmission control unit, I think LR call it EAT electronic Auto Transmission ECU

Click to expand...

sierrafery said:

TCU means "transmission controll unit"(named EAT ECU in RAVE), BCU is the body controll unit, not involved in shift controll

Click to expand...

DrecklyD2 said:

Under the passenger seat

Click to expand...

DrecklyD2 said:

You’ll need a switch, some wire, and a standard 30amp relay.
The reason for using a relay instead of a large resistor is it acts as a fail safe for the TCU. Even though you have manually energised the TC lockup the TCU still thinks it’s in control and will when it thinks it’s right will energise the TC. If a resistor is used it will short and put it in limp mode. So the TCU thinks it’s doing its job as it should.
The other reason is the TCU is constantly monitoring the system, if you splice in or cut the TC wire it will throw a fault and again enter limp mode. With the relay connected the TCU sees this as a connection to the Solenoid Valve as thinks all is well. Ok now I have bored the hell out of you here’s what you need to do.
1. Find pin 32 on the TCU, cut this wire but not too tight to the TCU.
2. Connect the wire from pin 32 to one of the pins on the relay. Either the + or - that energises the relay.
3. Connect a wire from the opposite side of the one you have just connected on the relay and splice it in to the wire on pin 53 which is the power supply to the solenoids. This connection allows the self diagnostics to see what it thinks is the solenoid valve.
4. Connect a length of wire to the wire that was connected to pin 32. Connect this to one terminal on your switch and the other to a good earth.
5. When you operate the switch you are supplying a direct ground to the TC solenoid valve which will energise it and lock your TC. You can do this in any gear, but don’t let it change gear when locked.
I hope all this makes sense, but let me know how you get on and if you have any questions please feel to ask.
Cheers
Tom.

Click to expand...

DrecklyD2 said:

Hi Stan
No worries mate.
I did explain about the relay and what would happen if the ecu energised while you were in control. It’s always easy when it’s in your head and you have done it a few times
Only the switch will energise TC as the solenoid connection from the ecu has been cut, however……and here is where it gets tricky. You can have both options. You in charge and the ecu but a different relay and wire setup will have to be used.
In its current setup If your switch is on and you are in control of the TC and the ecu wants to energise the TC it will in fact be energising the relay which is used to trick the ecu in to thinking it’s doing it’s job of energising the solenoid. This in turn stops any short circuits and faults and most importantly ecu damage.
The wire diagram is in my head along with lots of other weird and wonderful things
Give me a day, and I’ll get it down on paper for you along with PIN number and wire colours, I’ll try and get both options done as soon as I can.
Regards
Tom

Click to expand...

sierrafery said:

Did you ever retrieve fault codes from the EAT ECU since this setup was made? Cos i have the feeling that there are some faults logged which means that the addaptive values can be mixed up big time.

Click to expand...

DrecklyD2 said:

Hopefully this will clear things up a little. I have also used the correct wire colours.
View attachment 276326

Click to expand...

DrecklyD2 said:

You’ll need a switch, some wire, and a standard 30amp relay.
The reason for using a relay instead of a large resistor is it acts as a fail safe for the TCU. Even though you have manually energised the TC lockup the TCU still thinks it’s in control and will when it thinks it’s right will energise the TC. If a resistor is used it will short and put it in limp mode. So the TCU thinks it’s doing its job as it should.
The other reason is the TCU is constantly monitoring the system, if you splice in or cut the TC wire it will throw a fault and again enter limp mode. With the relay connected the TCU sees this as a connection to the Solenoid Valve as thinks all is well. Ok now I have bored the hell out of you here’s what you need to do.
1. Find pin 32 on the TCU, cut this wire but not too tight to the TCU.
2. Connect the wire from pin 32 to one of the pins on the relay. Either the + or - that energises the relay.
3. Connect a wire from the opposite side of the one you have just connected on the relay and splice it in to the wire on pin 53 which is the power supply to the solenoids. This connection allows the self diagnostics to see what it thinks is the solenoid valve.
4. Connect a length of wire to the wire that was connected to pin 32. Connect this to one terminal on your switch and the other to a good earth.
5. When you operate the switch you are supplying a direct ground to the TC solenoid valve which will energise it and lock your TC. You can do this in any gear, but don’t let it change gear when locked.
I hope all this makes sense, but let me know how you get on and if you have any questions please feel to ask.
Cheers
Tom.

Click to expand...

Iwandavies351 said:

Question, does the Tc lock in all gears or only 3rd and 4th? I am lloking at the same problem. Going to try a V8 TCU first and then maybe consider this job.

Click to expand...

DrecklyD2 said:

You can lock the TC in any gear. To make it smooth you have to learn the rpm pattern for each gear. To be totally honest 1st is no point, 2nd works really well here on the Moors when just cruising around between 20 and 30 mph. 3rd also works well 25 to 45mph.
One thing I have noticed through nano com is the engine can run from 5 to 8 degrees hotter.
Hope that helps.
Oh, while I'm at it. I have used the V8 TCU and I'd say don't bother, it will drive you mad as the torque values are very different between the TD5 and V8 and as a result its constantly changing gear at the slightest hint of throttle.

Click to expand...

DrecklyD2 said:

I have used the V8 TCU and I'd say don't bother, it will drive you mad

Click to expand...

sierrafery said:

IMO that's not a rule, as i said i've seen many such experiments and every time was a different outcome based on the elements which i've already revealed in the OP's other thread

Click to expand...