Disco 2 pre face lift cdl connection

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billrand

Active Member
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Hi folks ive read must be hundreds of items on connecting the existing cdl on a tc equiped td5.
Ive decided to go along the cheap option route using a flexible socket extension with various odds and ends running through the tunnel side wall.
Anyway this brings me to the question,,,there are multiple posts on how the tc reacts to this situation many contradicting each other,,ie the tc will fight with the cdl in some situations,,cutting the wire vs not cutting the wire,,when and how to engage cdl so it all works,,
im aware that the facelift models with both fitted had a less aggressive tc system to work with the cdl,ie it was developed to work as a complete system,,,whereas the preface lift tc system is actually when you think about it not designed to work hand in hand with the cdl.

thoughts? advive ? cheers chaps
 
Hi, the thing is very complex so in a nutshell: always lock the diff while the engine is running and you'll be OK, though if you get stuck this way turn ignition off then start again and continue, cutting the wire is a nonsense IMO.
 
sierrafery said:
Hi, the thing is very complex so in a nutshell: always lock the diff while the engine is running and you'll be OK, though if you get stuck this way turn ignition off then start again and continue, cutting the wire is a nonsense IMO.
Click to expand...

so following this, i use my truck for work mainly,,ie muddy tracks, woods, farmers fields etc,,so i pull up to the field, engage cdl while engine running get to job site. so far so good.

i pull up,,so i should then take the cdl out? turn off and slave away for the day, on return start engine engage cdl and pootle off?,,,,the only draw back isee with this is that to disengage we all know you have to travel a little distance before it does.

i suppose underlying my question is the fact that a converted truck has a far more aggresive tc system as its not callibrated for use with the cdl,, any forseeable problems?
 
billrand said:
so following this, i use my truck for work mainly,,ie muddy tracks, woods, farmers fields etc,,so i pull up to the field, engage cdl while engine running get to job site. so far so good.

i pull up,,so i should then take the cdl out? turn off and slave away for the day, on return start engine engage cdl and pootle off?,,,,the only draw back isee with this is that to disengage we all know you have to travel a little distance before it does.

i suppose underlying my question is the fact that a converted truck has a far more aggresive tc system as its not callibrated for use with the cdl,, any forseeable problems?
Click to expand...
cdl is designed to engage and disengage on the move as long as its not high speed and wheels arent spinning
 
billrand said:
so following this, i use my truck for work mainly,,ie muddy tracks, woods, farmers fields etc,,so i pull up to the field, engage cdl while engine running get to job site. so far so good.

i pull up,,so i should then take the cdl out? turn off and slave away for the day, on return start engine engage cdl and pootle off?,,,,the only draw back isee with this is that to disengage we all know you have to travel a little distance before it does.

i suppose underlying my question is the fact that a converted truck has a far more aggresive tc system as its not callibrated for use with the cdl,, any forseeable problems?
Click to expand...
You have to lock the diff with engine running only when you need it off road, if you get stuck this way turn ignition off and start again, this way theTC will be disabled... then once back on the road unlock the diff ASAP, eventually read the driving techniques in the owner's handbook, dont cut wires nor unplug things cos if you unplug the switch you'll not have the warning on dash so you can forget it locked and ruin it if you go on road with speed.
 
this is what i mean,,,two people two different opinions on the wiring problem,,,surely by now there is a deffinative conclusion?
 
this is what i mean by confusion,,,

From Ashcroft: http://www.ashcroft-transmissions.co.uk/part_17.html#pa2

1) Disconnect the battery. Unscrew the four hex screws in the glove box hinges. Reach round the side of the glove box with each hand and pull the closing mechanism upwards. Slide the glove box out

2) Pull out the 3 push-studs on the black cardboard panel underneath the glovebox, and undo the screw stud at the back. Remove the panel.

3) Near the outer side of the gap behind the glove box, you will see 2 or 3 ECUs, depending on whether you have ACE, I think. The SLABS ECU is the centre of the three, or the outside of the two. It has 5 black connector blocks underneath. Remove the centre block of the five from underneath the ECU.

4) Look for the black & blue wire running to pin 9 of the connector block, which is the central pin on the lower row, i.e. the row furthest from the retaining clips. At this point, make sure you have the right connector, and the right pin!

5) Cut this black & blue wire & tape off the ends. (Give enough space to solder it back together if you find out you have cut the wrong one...) Reconnect the connector. Replace the panel and the glovebox. Reconnect the battery.

Please note :

This is not needed for 2003 on (facelift) models as the ECU has been reprogrammed to take care of NOT disabling traction control/ABS when CDL in engaged, when ignition is switched on.

To test: engage the CDL and start the car up. The CDL light should be lit, but the ABS/TC lights should not be lit up. This is correct - it means that the SLABS ECU is not disabling ABS/TC when you start the car up with the diff lock engaged
 
billrand said:
This is correct - it means that the SLABS ECU is not disabling ABS/TC when you start the car up with the diff lock engaged
Click to expand...
the gist of it is the final statement: "To test: engage the CDL and start the car up. The CDL light should be lit, but the ABS/TC lights should not be lit up. This is correct - it means that the SLABS ECU is not disabling ABS/TC when you start the car up with the diff lock engaged" , now corroborate this with what i told you then i'll come back later with the full explanation based on bench tests with the ECU which i doubt that ashcroft or anybody else have bothered to do
 
billrand said:
you said engage cdl when the car was running lol
Click to expand...

Yes he did, because that is how you deal with CDL on a pre-facelift model.
Engage and disengage CDL with the engine running and the TC remains engaged. Engage CDL with the engine stopped and the TC and HDC are disabled.
Stop the engine with the CDL still engaged and the TC is disabled when you start until you move forward, disengage the CDL and stop and restart the engine.
It is at worst a minor inconvenience, and if as SF suggests, cutting wires inhibits the CDL warning light, then it is an inconvenience worth living with.
 
Si Click said:
Yes he did, because that is how you deal with CDL on a pre-facelift model.
Engage and disengage CDL with the engine running and the TC remains engaged. Engage CDL with the engine stopped and the TC and HDC are disabled.
Stop the engine with the CDL still engaged and the TC is disabled when you start until you move forward, disengage the CDL and stop and restart the engine.
It is at worst a minor inconvenience, and if as SF suggests, cutting wires inhibits the CDL warning light, then it is an inconvenience worth living with.
Click to expand...

thanks its slowly begining to make sense lol,,,only had a 200 and a 300 before it was oh so simple :),,
 
@Si Click explained exactly what happens but from bench tests i made when i compared the outputs of early SLABS ECU with the uprated SRD500070 i realised that in reality there is a difference beween the cut wire and CDL engaged with running engine as even the early SLABS has a different activity when it gets the CDL input, it's not exactly like with cut wire when for the SLABS the CDL is not engaged and there are rare cases when this can create a conflict and lose motion, happenned to me with cut wire in deep mud and i couldnt disengage the TC then to let the CDL work alone without any TC braking action, that's why i said in my first reply "always lock the diff while the engine is running and you'll be OK, though if you get stuck this way turn ignition off then start again and continue".

For those who think it's that simple to just cut the wire i can say with 100% certainty that even the early SLABS has a management for the TC + CDL scenario just that it's not that evolved like the uprated one and there are cases when the CDL without TC is better than with cut wire... believe me or not
 
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