D2 ACE & HDC lights on

HI there ive got a customers 2002 TD5 disco in to clear come faults but i cant clear the ACE and HDC lights .

the disco came in with the hand brake, ABS, HDC ,ACE lights and i cant be sure but the traction control may have been on also and on start up im getting 6 chimes as i turn on the ignition . the abs had some historical faults" left front and rear air gap to large", that was cleared but one" brake lamp relay power amp" fault is stilll there and will not clear .also the ACE is not responding to any tests (bleeding, system test etc)

any help will be great

1. The brake lamp relay fault keeps the HDC on...it will go off just after the fault will be eliminated... unfortunatelly i couldnt find out untill now where this relay is(if u will, tell me too) see this http://www.landyzone.co.uk/lz/f8/diagrams-vs-reality-mystery-am-i-dumb-160328.html

2. This kind of ACE behaviour usually is due to missing ignition signal/voltage/earth at the ECU ...did u check the ACE relay and fuse (F15, R14 engine bay)? If these are good and no fault codes logged u have to take a multimeter and check for earth and voltage inputs on the ACE ECU multiplug. Pin 11, 28 (+12V) and pin 20 and 32 earth.

hey thank you so much for your help ....

ive checked fuses and swapped around the relays and checked the ACE multiplug and there is no supply at # 28 all the rest seem fine . where does it get supply from ? can i supply it with power via a diffrent wire ?

i havent checked the brake power relay yet

Pin 28 at ECU gets feed direct from F15 through the ACE relay's contact on PO wire from C0574 pin 7 engine bay(then it's understandable it doesnt work) ... see RAVE connector views...(and the diagram). I had something similar once and it was a bad contact within the fusebox... the connections between circuits and pins within this are made through some matal "lays" which can corrode. See if u have voltage after the relay. If u want to run a direct wire make sure it's from this relay's output.

ok then i will open the fusebox and have a look . i am also getting a fault "engine speed signal to high "

on the HDC i just pushed in some loose multiplugs at the back of the fusebox and the light went out and the fault was able to clear

This code is generated by the crankshaft position sensor ....

On which fusobox did u push multiplug for HDC? ... on the passenger compartment one?

yes passenger compartment

ive checked the engine fuse box and the continuity between the relay pin and the multiplug is good and the wire from the ACE ECU to the fusebox is also good but im not getting any current after the relay . i suspect the ground (earth ) isnt good

i cant seem to bypass the realy without a fault comming up sayin main relay fault logged.

defcrazy said:

yes passenger compartment

ive checked the engine fuse box and the continuity between the relay pin and the multiplug is good and the wire from the ACE ECU to the fusebox is also good but im not getting any current after the relay . i suspect the ground (earth ) isnt good

Click to expand...

take out the relay and see if u have voltage on it's coil and one side of the contact with ignition on ... u can follow the voltage path if u check the diagram.

well after many attempts to sort the relay and its fault i found that the ACE ECU was not sending a signal from pin # 6 (ARC relay) to energise the relay . only then did i remember that i had a ECU from another disco , so i plugged it in and the light went out and the faults were cleared

Again ,sierrafery thank you soo much for all your time & help

Welcome and i'm glad u sorted it... anyway ACE ECU failures are quite rare, but as u saw with measurements(following the diagrams and pin connections) u can get to the end of it. Remember that if an ECU gets all the inputs, but one(or more) outputs are missing(at his plug off course) then go for another.

well some of the lights are back . just as the customer picked up the disco and drove off he called and said the hand brake ,Traction control and ABS lights came on . so i told him to switch off and restart and the TC and Hand brake went off and as he drove off the ABS went out after . so he will be bringing it back some day soon . i wonder what could be wrong now ?? i did have one disco that did this one or twice but it never logged a fault

Get hold of a good SLABS ECU too.... unless u got one of the SVS faults logged.

sierrafery said:

Get hold of a good SLABS ECU too.... unless u got one of the SVS faults logged.

Click to expand...

i have one but im not sure its any good . im guessing SVS is shuttle valve switch ,if so then he said its been changed ,but it did have a historical SVS fault when i started

well the customer came back with the disco and the only fault was left front sensor broken wire .and left front signal too low or high . so i put a new sensor and drove it a few times over three days and the lights have not come back. im glad to be rid of it