After finally getting the bike started after the winter, (new fuel injection ECU), the ABS system is playing up, (please see "Warning light problem" thread).

The situation is as follows;

• ABS and main warning light start flashing together as soon as the ignition is turned on.
  
• If the ABS button is pressed, the lights stay on permanently for about 10 minutes, then revert to flashing. (Does this imply that the ECU is partly working, or is there a timer on the warning light relay?)
  
• ABS does not work
  
• I've connected a test meter between the middle contact of the diagnostic socket and earth and get 7 "blips", which indicates a fault with the ABS ECU
  
• I've tried resetting the ECU by connecting a wire from the central diagnostic socket contact to earth, holding down the ABS switch, turning ignition on, holding the switch down for 20 seconds then turning the ignition off. No joy.
  

Any ideas, other than to replace the ECU? (I don't fancy a £300 bill, if I can help it). If not, any suggestions where to get an ECU? (I've looked on e-bay).


Simon

1991 K100LT

SDR,
If it has been standing and it was OK before, then I would clean every contact I could find in relation to the ABS. This is about the only thing that could go wrong when just standing. Also shine up the teeth pick up on the wheels.
Ajays

I stripped 2 K1100's down last year with ABS - on BOTH bikes the Brain connections looked like they'd been sprayed with green fur ! OK, slight exageration.

In both cases the previous owners had experienced "trouble" with the ABS. Both sets worked perfectly after a good clean and lube of all the contacts.

In fact, ANY new to me Kay now gets that treatment on all the electrical contacts. Oh yes - and ABS gets stripped off and sold on!

contact cleaner http://uk.farnell.com/cramolin/contaclean-400ml/cleaner-contaclean-400ml/dp/840038
Ray

I don't have ABS on my bikes and don't have any experience with it.
I found the following information on a French BMW site and translated the post.

Reading the ABS fault memory:
Find the brown/white wire on the diagnostic plug. (The diagnostic plug is a small plug with 3 wires. It’s situated on the right side between the electrical tray and the ignition/FI computer)
Plug a low intensity light (12v LED is the best) between this wire and positive of the battery.
Turn the ignition ON.

o No flashing, all is good
o 1 flash: Fault in the front modulator
o 2 flashes: Fault in the back modulator
o 3 flashes: Fault in the front sensor
o 4 flashes: Fault in the back sensor
o 5 flashes: voltage of the battery too low
o 6 flashes: Fault with ABS relay
o 7 flashes: Fault in the ABS computer
o 8 flashes: Need to reset the computer

Flashing the fault memory:
- Plug the brown/white wire of the diagnostic plug to the positive of the battery
- Turn the ignition ON for few seconds
- Turn off the ignition
- Plug the brown/white wire to the ground
- Turn the ignition ON again
- Push the ABS button on the dash for 30 seconds
- Turn OFF the ignition

Thanks Crazy Frog,

Do you happen to know / does the website state whether the procedure for flashing the unit applies to ABS 1, which is what I have, or ABS2? I don't want to ruin the ECU by getting it wrong.

Simon

Update: success!

Contacts cleaned, rotors cleaned and ECU flashed. ABS now working fine. 20 mile ride completed, no problems.

Thanks to all who suggested fixes; you've saved me a large bill.

Simon

Result.

nice when it's a cheap fix