2 amigos ???

defcrazy · Aug 22, 2011

hi there ive got a strange problem on one of my customers 1999 Disco TD5 . the hand brake and ABS lights are on all the time . there was a problem on the right rear wheel sensor so we fitted a new one . all the other ones were replaced a few years ago ,along with a new ABS pump and ABS ECU but they dont show any faults on the Hawkeye . there are no new faults after we cleared the stored ones . any help will be great

sierrafery · Aug 22, 2011

Strange... are u sure that the TC and HDC lights are working? do they enlight on self test? if not then u have a 4 amigos on ... u can see the table of faults here http://www.landyzone.co.uk/lz/f8/disco-11-abs-fault-161080.html if the other 2 lamps are working then it must be a false feed or ECU missbehaviour issue and we'll talk again how u can check this

defcrazy · Aug 22, 2011

yes the HDC and the TC lights are working ,on self test and go out after start up .

sierrafery · Aug 22, 2011

OK then. It might be a bit complicated(i mean u might have to work a bit to reach the SLABS ECU, handbrake switch or some hard reachable connectors) are u up to that?.... cos i'm sure that's diagnosticable IF:
1. u have RAVE
2. U have some ideea about electrical ciscuits and u can handle a multimeter

First thing to check is that where is this fault's origin.

Update > i've checked a few things .... untill u'll confirm or not some suppositions of mine i have to think it's an ECU missbehaviour ... unless there are two faults unrelated(not very obvious but possible)

defcrazy · Aug 23, 2011

yea im up to it . but my customer is using the disco (its his only car ) . so im just trying to get some info on what to check and how to check it so when he comes in for service or sumthing i can sort it out

sierrafery · Aug 23, 2011

The easyest way would be to take out this ECU and put it in a good car(dont be affraid it can't mess nothing up... of course disconnect battery before the swap) ... if the two light will show themselves on the other car too then a new(or known good ECU) is needed.

IF u dont have the possibility to do that then u have to work a bit:

1. The easyest first check... disconnect an ABS sensor and go for a ride... the TC and HDC must come on this way... if they doesnt it means the ECU is faulty.
2. u have to reach the Slabs ECU and disconnect first C0504(u find the disposal in RAVE Brakes description and operation)
3. if the brake and ABS light will go off both, put it back and go further disconnecting one by one the multiplugs(except C0655) .. for all the other plugs disconnected the TC and HDC must come on.
4. If just the ABS light goes off then u have 2 different fault and one might be with the handbrake switch.
5. if both light will stay on with C0504 disconnected it means there is a short circuit somewhere

I think it's enough for now

defcrazy · Aug 23, 2011

sierrafery said:
The easyest way would be to take out this ECU and put it in a good car(dont be affraid it can't mess nothing up... of course disconnect battery before the swap) ... if the two light will show themselves on the other car too then a new(or known good ECU) is needed.

IF u dont have the possibility to do that then u have to work a bit:

1. The easyest first check... disconnect an ABS sensor and go for a ride... the TC and HDC must come on this way... if they doesnt it means the ECU is faulty.
2. u have to reach the Slabs ECU and disconnect first C0504(u find the disposal in RAVE Brakes description and operation)
3. if the brake and ABS light will go off both, put it back and go further disconnecting one by one the multiplugs(except C0655) .. for all the other plugs disconnected the TC and HDC must come on.
4. If just the ABS light goes off then u have 2 different fault and one might be with the handbrake switch.
5. if both light will stay on with C0504 disconnected it means there is a short circuit somewhere

I think it's enough for now

thank you soo much . this will help out alot because i was stumped and didnt know what to do next

sierrafery · Aug 23, 2011

Welcome...and be aware after all this kind of tests dont be amazed if it will be full of logged codes.... a tester might be a big help... for example: after u've disconnected and reconnected C0505, if the ECU is faultless u have to find fault codes for all the four abs sensors ... and similar for C0506...see the table in RAVE with pin correspondence and u have to find open circuit/data lose fault codes for every one of it after disconnecting... do u see what i mean?

2 amigos ???

defcrazy

Active Member

sierrafery

Well-Known Member

defcrazy

Active Member

sierrafery

Well-Known Member

defcrazy

Active Member

sierrafery

Well-Known Member

defcrazy

Active Member

sierrafery

Well-Known Member

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