Hope you get to the bottom of it. Some times a car can't lock its brakes up because they're so weak even if you stand on them hard. You should hear it working, but some cars have really quiet ABS operation.
Somethings happening. A resistance check in the led socket as you turn the ignition on should show a closed circuit, if not do the same check following the wire back through each connector until you get to the ECU pin. Hopefully digging around under the dash will restore continuity to the circuit. Last resort would be to put your own wire in, but I would shy away from that idea. Its most likely a miss crimped spade in there somewhere, or unlikely a failed board component(diode, dry joint) in the ABS ECU. Has the ECU got a dedicated earth path for the ABS light? Just be methodical and use your eyes!
You can measure the voltage between Connector A pin 18 and chassis (ground).
To lite up the LED pin 18 should be pulled to ground (0V) else you should measure 12V or close to 12V when not lite up
Its a one off fault that can be sorted, just a bit of an adventure I'm sure you can sort out. Make yourself some fine pointy probe tips and start looking for the coloured wire at the respective connections, theres only a couple by the looks of things! You are spoilt by having a wire diagram.
Managed to get the light to come on using a multimeter and help from forum member PKR so the fault appears to be within the ECU itself. At least the pump unit does'nt need changing!
If you recall, I tested the resistance between ABS unit and car body. It was fine. That doesn't rule out an intermittent problem of course, but the fact that the ABS light came on when pin 1 was connected to the ABS unit body and that the ABS appears to function in a brake test is indicative that the earth isn't a problem.
That's what I thought but who knows with Alfa electrics! lol Was unable to strip the ECU down in situ inspite of removing the brake fluid reservoir and relay fuse box so will have to take it to Marco.
Air-bag light is back on again - after changing the headlight dip beam bulb!!! arrrrrrrrgh!
You'll learn where all the connectors are in time lol. Take the ECU out, if you're careful with the reservoir you won't have to bleed the brakes! Sounds like you have some damp issues with the electrics and earths, lots of electrical cleaner n copper grease, maybe crimp in some new earth terminals?
Its hard to light this time of year! lol. Most ECU earths are near it! It may have its own earth and not share it with another system, most ECU's will have several earth wires.
Just a update on the above, on investigation i've found pins 3 and 4 are incorrect on the phase 1 wiring diagram they should be transposed to be correct. signal LTB-WHT wire is on pin4, earth BLK wire is pin3 of the square ECU connector G272.
Alfa_Awfulsod Thanks for the original post, I hadn't even noticed my ABS had no warning light on startup.
New ABS module ECU sorted mine. Bought the 0 265 204 001 block and ECU off Ebay in Tokyo! only one i could find
Can't you bend the taps up and ply it apart, or is it molded into a block of resin? Ring around ECU repairers, some may take on the work FOC, but you may have to pay their postage rates? Not a shared part that could be reprogrammed for your car? Good luck with the hen's teeth, they aren't that rare!
Seems to be a sealed unit and part of the ABS module as a whole. If I removed the ABS unit to try and get the ECU repaired it might be as easy to fit a complete replacement unit - just need to find one!
If push comes to shove you could remove abs unit altogether, it's not a mot requirement to be fitted. Just join the brake lines up with connector blocks. Would also have to do something about warning light also.
I still have a problem with my ABS unit not iluminating the warning light on the dash, I also have a simular problem With the charging light not iluminating, the battery are charing With 14,2 V so ok there
Anyone know if the two problems can be the same?
Does anyone have a wiring diagram for the binnacles and the charging system ? I am interested where the 12V to the light bulbs/ LED comes from ? ,
If anyone want to sell me a copy of a repair CD I would like that ;-)
You haven't mentioned what model your car is.
Is it a Ph1 or and Ph2? The instrument cluster is different between the two models.
Do you have problem with other indicator lights.
The 12V for the ABS and Generator light come from the same line.
It is the key-operated 12V on pin 2 on the B connector on the instrument cluster.
If this voltage isn't present you will also have problem with the following warning lights:
I have been dooing some Things during the weekend, I changed the ABS hydraulicpump With ECU, With no different, the changed the binnacle, and then the light cam back ;-) but now it remains there so I will have to find the fault in the system to
Hello
Problem solved.
Both my binnacle and the ABS ECU had to be changed, but left me With a ABS illuminating on the dash, then I put Earth to the ABS testerplug and read out the code on the ABS light , it said ABS sensor defectiv, measures the sensors they where oki, the it was the wiring left, found a broken wire where it Connects to the ABS ecu, solded and all OK, thanks to Henrik for help ;-)
Regards
CHris
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