Thread: HDC and TC lights only (not ABS) staying on after BCU/ECU/IDM change

No, nothing like that, the TC + HDC without ABS according to the official diagnostic protocol is "Engine data = Sticking throttle, signal failure, data corruption" (3'rd in the attached list) which should be stored as fault code BUT in reality i've seen cases when these warnings were on without any code stored but intermittent and in this case you'll have to drive it hard and brake alot untill the ABS comes on too then you'll get a fault code usually a sensor related one also.

Many thanks mate. The odd thing is that if it be engine management related the HDC is not working. But if i understand it correctly you think it might be ABS related? I will attach my ultra guage and see if any codes. It did not have the warning lights nor codes before the no-start issue...

Cheers

I do wonder how D3/4's could be any more complex in their mechanical safety interlocks,,
I think the car thought there was a safety problem,,
and stopped the car.

sounds good!

What is annoying me is that a Testbook equivalent was hooked up on it and pronounced all OK after the programming saw it start up....

Ok gauge on and it's throwing a 0600 code which I understand to mean a missing signal from the transmission control module (which perhaps mine does not have because it's an auto)...so because my ECU and BCU and IDM came from an automatic it logs an error...if that be the case the question is whether the BCU can be reprogrammed to instruct it that the vehicle is a manual transmission...

It might also explain why HDC is not able to be engaged because it needs to know what the trans is doing.

Cheers

Yes, deffinitely the BCU must be set for manual transmission if it wasn't already cos it should throw flashing M+S if it was on auto setting but IMO that automatic engine ECU will still miss that CAN signal and missing that it gives corrupted data to the SLABS that's the reason for TC/HDC warnings, was the ABS ECU scanned too...if there is a current fault present the ABS AMIGO can't clear it, do somehow to read the fault code stored in the ABS...and if no code wait untill the 3 amigos will be complete and read then... the HDC or TC will not work as long as the warnings are on and the ABS is in a default mode with reduced deceleration threshold too

i know too little about the V8 engine management but IMO an automatic ECU should be remapped for manual as to not expect that CAN message from the autobox ECU which is not there

This might be a problem...lack of resistors in the auto ECU for clutch pedal recognition...re HDC feeds...

http://www.aulro.com/afvb/discovery-...-td5-ecus.html

Cheers

Something like that though in the linked thread it's about Td5 and the V8 ECU is way too different but the clutch switch input is also needed that's a fact... as the BCU is set to manual this info is shared with the SLABS too then the SLABS doesnt get the expected specific manual inputs from the automatic ECU and it throws that "corrupted data" fault code which brings up the HDC/TC warnings when HDC is disabled, IMO better get hold of a manual ECU