Well it looks like I may be at long last getting somewherewith my long running ALBS issue. Torecap, the warning light was illuminated the whole time from ignition on toignition off so I couldn’t even get a “flash code” fault diagnosis because thelight was on the whole time even when the diagnostic socket was bridged.
Tried all the 32 electrical diagnostic checks in the manualand had no faults. Tried a second hand (guaranteed) ECM and still constant warninglight. Went back to basics and established which supplies to the ECM werelive, earthed, had continuity etc. then sat down with a wiring diagram topuzzle it all out.
The key clues that finally got me thinking were:

• According to my handbook the ALBS light should,after the normal check sequence, illuminate on cranking (ignition switchposition 3) as a bulb check;
• According to the wiring diagram the supply topin 19 of the ECM should provide 12V on cranking only so I presume causes thebulb check as above (note that the main feed to the ECM whilst the ignition ison comes in to pin 2).

I discovered that the supply to pin 19 was live the wholetime the ignition was on (ignition switch position 2 or 3) so wondered if anupstream wiring fault was causing the bulb check circuit to run the whole timeand keep the warning light continuously illuminated. Rather than pull the wholecar apart I used sellotape to wrap around pin 19 of the ECM to isolate it (youneed tape, tweezers, surgical scissors and a magnifying glass).
Plugged in the ECM and the ALBS warning light did exactly asit should – short illuminated test sequence then off. Tried a fault code checkby bridging the diagnostic socket and for the first time ever got a flash code(2 – 1, a valve block fault). Then I remembered I was using the second hand ECMwhich may have had a previous fault code stored. Drove the car above the faultreset speed, tried again and hey presto no fault code.
I am no way suggesting this is a permanent fix (in any case Ihave now lost the bulb check facility and still have to test the ALBS in anger)but it has helped me identify the likely cause i.e., a problem with the wiringto pin 19 upstream of the ECM and not the ALBS system itself. So the searchcontinues but in a different direction.
Sorry to labour the above but I have spent 6 months on thisand have not seen anything similar reported so hopefully this may help someoneelse in the future.
Now if anyone has any ideas as to how the wires to pin 19may have got crossed I am all ears!
Cheers,
LeeP

 

From looking at my wiring diagram l suggest maybe the feed to pin 2 (white wire/ ignition feed) and your white/yellow to pin 19 are in contact. They both show at connector CP7 at the centre console. You might be able to unplug there and run test. Might even be something bridging at the connector itself.

 

Lee,

I'm so very pleased to hear that you might be getting there! As suggested, I think you're going to have to check back at each bridge stage of wire to Pin 19 and perhaps run an independent wire from each last known good point to Pin 19 until you identify where the break or cross might be.

Good luck!

Paul

 

Thanks Paul and also for your off-line support, help and advise.
LeeP