[s-cars] "Antilock off" caused by diff lock vacuum failure
wd43 at hevanet.com
Sat Nov 7 14:12:16 PST 2009
I've been chasing an intermittent "antilock off" light for a while and
haven't noticed any postings about what failed in mine. The first
breakthrough was noticing the light seemed related to acceleration. The 2nd
was noticing that it was directly related to vacuum and boost levels, and
the 3rd was that the diff lock's green light went came on and went off with
the antilock off light. I actually had 2 failures: (1) The vacuum check
valve under the back seat was open in both directions, and (2) the hose
nipple had broken off of the vacuum resevoir in the trunk.
I replaced the check valve with a $4 generic version from the parts store.
It's very difficult to get to the clamp on the original check valve so I
just added the new valve in line with the old one. I glued the nipple back
onto the vacuum resevoir, but this is a type of plastic that glue doesn't
stick to very well so it may or may not stand the test of time. Besides
fixing the antilock off problem I'm noticing a smoother application of boost
pressure. Before the fix, the boost would climb to about 20 psi then
abrubtly back off to 10 psi or so. Now it climbs to 15 psi, smoothly tapers
off, and holds at 15. I assume the leak was causing the ECU to be getting
corrupted vacuum/boost data.
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