My first attempt at disabling ABS without influencing the working of the traction control was to prevent the ABS ECU from "seeing" the brake pedal input. The thinking here was that the ECU used the brake pedal as in input to decide when to activate ABS.
I passed the C0504 Pin7 and Pin14 connections through a DPDT pushbutton switch in the cubby that fed the ECU with a fixed state (NC for Pin7 and NO for Pin14) when the pushbutton was pressed. This meant that the ABS ECU always thought that the brakes were released even when pressing the brake pedal. Releasing the pushbutton switch meant everything worked as normal.

This didn't work! The ABS still activated even though the ECU didn't see the brake pedal state changing.
My assumption was wrong and the ABS ECU doesn't use the brake pedal as an input to activate the ABS. This also means that ABS will activate even when you are not pressing the brakes but only slowing down using engine braking. I've have since experienced this on a steep muddy descent.

I think this means that the ABS is only monitoring the wheel speeds and if the average is decelerating then ABS is "armed" and ready to intervene if one wheel is decelerating quicker than the others.
The inverse would also then be true for the Traction Control (TC). If the average of the wheel speeds is accelerating then the TC is "armed" and intervenes if a single wheel on an axle is accelerating faster than it's counterpart (or the average, I'm not sure, but RAVE seems to imply the average).

My current plan is to intercept the drive signals to the ABS Booster unit and prevent the solenoid valves booster unit from being energized when the ABS ECU attempts to do so.
This should allow me to either prevent ABS activation or to prevent TC activation (loose sand).

Any thoughts?

Hi Dave,
How did you finish the edges of the sheet metal to prevent rust?
I have a raised air intake that I'd like to get fitted this December, but I haven't decided how to deal with the cut edge of the sheet metal. It doesn't need to be pretty since the intake will cover it by quite a margin, but I don't want it to rust under there!

I've also just purchased a 3D printer, so at some stage I'll ask you to please send me your fuel pump cover files. Probably next year sometime.
Your cover looks good!

I got my BBS MSV licensed for the full P38 yesterday, and also fitted and tested the new to me UK ECM.
The ECM now enters closed loop fueling and is adjusting the trims. That's a win!

ABS Controller & Connector Info

C0504
Junior Power Timer, 17P
Partnumber: 1355204-1 (black housing, not available)
Alternative Partnumber: 1355204-2 (red housing, unconfirmed fit)

C0505
Junior Power Timer, 9P
Partnumber: 1-967621-4 (Grey)

C0506
Junior Power Timer, 15P
Partnumber: 1-967623-1 (Purple)

ABS & Traction Control Solenoid Drivers:
Infineon BTS612N1 (Smart Two Channel High-Side Power Switch)
Various output protections as well as open load & short circuit diagnostic capability.

Yes, I've already adjusted the pot on the back of the cluster, and the speedo now over reads by 1km/h at 100km/h. Perfect, but the trip meter still under reads by around 9.8% (if I remember correctly).

While I'm busy with the ABS disable I might aswell get the speed signal to the BECM sorted too 😀
(and do it in such a way that removing a bit of plug and play hardware reverts things back to standard).

Gathering data.

Rough Road Signal:
ABS Controller C0504-Pin4 --> ECM C0637-Pin34
Amplitude: Battery Voltage
Frequency: 2.38Hz
Duty Cycle: 25% = Rough Road OFF
75% = Rough Road ON

ABS Warning Light Signal:
ABS Controller C0504-Pin18 --> BECM C1288-Pin10
Amplitude: Battery Voltage
Frequency: 5Hz
Duty Cycle: 50% = Warning Light ON
100% = Warning Light OFF

Traction Control Warning Light Signal:
ABS Controller C0504-Pin17 --> BECM C1289-Pin12
Amplitude: Battery Voltage
Frequency: 5Hz
Duty Cycle: 50% = Warning Light ON
100% = Warning Light OFF

Speed Signal:
ABS Controller C0504-Pin3 --> BECM C1289-Pin11
Amplitude: Battery Voltage
Duty Cycle: 50%
Frequency: Varies with speed (detail to be added)
221.7Hz = 100mph = 160.3km/h

ABS Schematic Diagram (2001 Petrol)

I'm going to use this thread to just dump information as I gather it, and perhaps think out loud about what I'm busy with. Chime in if you have anything to add, please!
Also, all information here is possibly correct, possibly not. Use it at your own risk! (especially because what I do here might interfere with the vehicles ability to stop)

Vehicle:
2001 4.6 HSE Thor.

Aim:
1) Develop a controller that will allow me to intercept and correct the speed signal from the ABS controller to the BECM to correct for different diameter tires.
2) Have a way to disable ABS at the push of a button without interfering with the working of the traction control.

Thanks for all the options, all would work great except that I actually want to maintain the ability to do diagnostics.
I've spoken to BBS and it is a hard no from their side, no-upgrade fee structures are possible so it is the full 1500EUR for me.

I'm just waiting for the exchange rate to improve a little and then I'll bite the bullet and buy the full P38 vehicle license to replace my VIN locked one.

The immobilizer fix looks like a really interesting project, I've been following PsiDOC's thread here and on RR.net.
I'm half tempted to get one just to play around with!

Anyway, there is absolutely no rush for me to get any of this done, the RR is running beautifully and getting used quite a bit.

In my case I went for the Faultmate because it requires a laptop to do diagnostics (a con for many) but I prefer the user interface of a laptop over the handheld display of the Nanocom. Additionally the SM035 module is only available for the Faultmate, not the Nanocom. The SM035 module allows a deeper dive into the BECM and is something most users will never need or use, they would rather pay for this service. In my case, being here is SA far away from such services, I decided to rather have this available as an option should I need it.

For better or worse that was my thinking while choosing the Faultmate just over a year ago. I also bought a little cheap laptop that lives behind the seat in the RR to be used with the Faultmate and this laptop obviously has the RAVE manuals on it and all the other bits of faultfinding and diagnostic information that I collect as I go along. Nice to have it right there always in the car when needed!

I have contacted BBS again and pointed out again that I would like to "upgrade" from a single VIN license to the full monty and if they are not willing to offer a reduced upgrade fee instead of the full amount. I'm hoping they are willing, it'll make the capital outlay much less making the decision to upgrade easier to stomach.

Hi Dave,
Yes, I am locked to a single VIN.
I have discussed upgrading to the fully monty covering all P38s, but they are unwilling to offer me credit for the modules already purchased.

How did you manage to upgrade from the single VIN license? Or did you pay the full price?

Full Monty is this: https://blackbox-solutions.com/shop/product/mp112
VIN Locked: https://blackbox-solutions.com/shop/product/mp015 (this is what I have, but I have also added SM029 to read all the newer gearbox ECUs)

Update:
The new to me ECU has arrived from the UK, but I have hit an unforeseen hurdle. I need to update the immobilization code in the BECM to match the ECU (which my Faultmate can do and was expected) but I can't access the new ECU with the Faultmate because it is locked to the serial number of my old ECU.

Is there some other way for me to read the immobilization code from the new ECU? An "unlocked" software module from BBS that will be able to read bot ECU's costs 175EUR, which is quite a bit, so if there is a cheaper way of finding the immobilization code then that would be awesome!

Haha! Maybe, maybe not.
I like the P38, and I wouldn't mind another in the family once this one is they way I like it!

Ah, I wasn't aware of that. Oh well, now I know for next time.

I also thought of doing that, but I decided that the risk is that the 2nd hand ECM I purchase might have some fault and the only way of knowing would be to test it. Having the quite expensive Tornado map loaded on it and then finding out that the controller is faulty would be a bit of an expensive realization!
Hence the roundabout way of doing it.

ECM ordered from Ebay. Thanks for the tip! It should arrive with my freight courier by next week and then will likely take another week to get to me.

Interesting story, so weird how things have changed. Now SAA has been managed into the ground, had bailouts from our government to the tune of around 21billion over the past few years and still they are not a going concern. What car club did you run if I may ask?

I didn't even think of using ebay, thanks Richard!

Yes, I have a Faultmate MSV2, with which I believe I can change the ECM security code on the BECM to match the ECM (as I understand it).
At the moment I'm willing to take the risk for the cost of the ECM, but if someone has done this and can confirm that it does/doesn't work as I described here that would be great and I can then adjust my plan as required.

Hi all,

Hoping someone might be willing to help me out.
I would like to send my ECM to the UK to have it Tornado-ed by Mark Adams, but I would like the car to remain mobile so I need another ECM to keep the car running here in SA while my original ECM is travelling. Additionally I also want an ECM with the Lambda/Oxygen sensor control activated for the two upstream sensors, hence my need for a UK ECM.

All this for a 2001 4.6 Thor (Bosch) car.

Would anyone be willing to purchase an ECM for me there in the UK from an appropriate vehicle and then send it on to my freight forwarder in London who will then get it to me here in SA.
Obviously I'm happy to pay for all related expenses, I'm assuming Paypal would be easiest?

Cheers,
Justus

Thanks for the correction Richard! Post above edited so as not to confuse anyone.

I am by no means an expert, so please take my thoughts with a pinch of salt!
All I can imagine is that the reduction hub isn't moving through it's full range of motion for some reason. Either the selector fork assy and interlock spool are not moving as they should or perhaps the selector and reduction hub are not mated correctly?

Another thought:
EDIT: removed because I was talking rubbish. Thanks for the correction Richard.

I had my transfercase in low when reassembling it, tested the high/neutral/low was all working on the bench, selected high range, counted the rotations to confirm and then refitted the ratio control motor that had been left in high range when removing it from the car. This seems to have worked for me.