My 1989 xj40 was acting strange when I applied the brakes on initial drive.
I would often feel the abs activate when I first started off, even in
reverse. This has gone away, but now my VCM shows “abs failure”. Any
ideas? What should I check?
Thanks,
Don
When I press on the brake, I feel the abs thumb and a buzzing sound. What
is happening? What should I do? Any thoughts would be appreciated.
Thanks,
Don
89 xj40
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Don wrote:
When I press on the brake, I feel the abs thumb and a buzzing sound. What
is happening? What should I do? Any thoughts would be appreciated.
Thanks,
Don
89 xj40
Your car has the engine-driven hydraulic booster if it’s MY89, or the
electric pump booster near the brake master cylinder if it was built in
'89 in July or later - which is it? Do you have any warning lights with
this behavior?
Dave Lokensgard
'90 Vanden Plas Majestic (DAVZCAT)
'55 XK140 OTS
Poway, California
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hi
i have posted this problem here before and I thought I had solved
the problem.
but I havnt.
my abs light is on I had a blink code 21 fault.the car went into
several garages who checked everything and everything is fine I
changed the abs ecu and that seemed to resolve the problem but
after a couple of weeks I have the same fault back and also vcm
says fault and no code. any ideas of were I need to go.–
kayla72
st helens, United Kingdom
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In reply to a message from kayla72 sent Thu 20 Nov 2014:
You say that several garages checked everything ‘‘and
everything is fine’’? Well, obviously not if you are getting
the ABS warning light and a ‘code 21’ on the Teves blink test.
As I said in response to your previous post on this subject,
a ‘code 21’ on its own indicates a problem with the ABS
main valve - or its connections at the valve or the ABS ECU.
Your VCM LCD display shows ‘FAULT’??? Are you sure it
doesn’t say ‘FAIL’? That would indicate a loss of brake
boost/ABS pressure or a loss of brake fluid which will of
course flag an ABS warning light.
You still haven’t told us the year and model of your car.–
The original message included these comments:
I have posted this problem here before and I thought I had solved
the problem.
but I havnt.
my abs light is on I had a blink code 21 fault.the car went into
several garages who checked everything and everything is fine I
changed the abs ecu and that seemed to resolve the problem but
after a couple of weeks I have the same fault back and also vcm
says fault and no code. any ideas of were I need to go.
–
Bryan N, now Jag-less, but fun while it lasted.
Cambridgeshire, United Kingdom
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In reply to a message from Bryan N sent Thu 20 Nov 2014:
hi sorry it is a 1992 jaguar xj40 soverign.
yes its says fail not fault. sorry
i have changed ecu. had speed sensors cleaned and checked. had all
electrical and relays checked by an auto electrician.
the accumalator charges and after 30 pushes on the brake pedal it
hardens up.
she hardly has been used over the last five years and has not had
a brake fluid change could this cause the problem or do you think
the first port of call would be to change the abs pump
cheers stuart–
kayla72
st helens, United Kingdom
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In reply to a message from kayla72 sent Thu 20 Nov 2014:
first thing i d try, is stick �50 worth of fuel in it and go and
take it for a damn good drive. one thing I say, time and time again
to folk, is cars do not like standing doing nothing, especially 25
year old cars, they are nt made for it!
give it a good run, come back and find a nice quiet street
somewhere and exercise the ABS. drive along at 20 mph then stand
on the brake pedal so the abs cuts in. repeat a couple of times.
take the car back home, disconnect battery for an hour, reconnect
and see what happens.
don t forget any radio codes etc on disconnect!
try and take the car out at least once a fortnight.–
The original message included these comments:
she hardly has been used over the last five years and has not had
kayla72
st helens, United Kingdom
–
1992 XJ40 4.0 LITRE
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In reply to a message from kayla72 sent Thu 20 Nov 2014:
Stuart,
OK - if you are getting 30+ brake applications after engine
shut-down before you lose brake boost (i.e. the pedal goes
hard) then there is nothing wrong with your brake
accumulator or ABS pump. That means that the ‘FAIL’ message
on the VCM LCD display cannot mean that you have a ‘genuine’
boost pressure problem - and that leaves the possibility
that the ‘FAIL’ message refers to low brake fluid levels in
the reservoir (or an electrical glitch in the connectors at
the reservoir or the combined pressure switch on the
accumulator mounting)
As I have mentioned previously, in my experience, you will
get a ‘code 21’ whenever you have any other fault on the ABS
circuit but normally you would see another code indicating
what that other fault is - but it and the code 21 will be
cleared when the other fault is corrected and after the car
is driven above 30 kph. However, I say ‘normally’ because
one other feature of the blink test is that it will only
show the lowest number fault code within that group of ten
(i.e 20 to 29, 30 to 39 etc) even when a fault which would
generate another higher code number in that group of ten is
present.
i.e. If you have a fault in any other valve in the ABS valve
block which would generate a code, say, 22 (inlet valve,
front left), you will not see that code 22 because it will
only flag the first code in that group of ten - i.e the
code 21.
It could well be that one of the other six valves in the ABS
valve block (inlet and outlet front left, front right and
both rears - codes 22 thru’ 27) is contaminated by muck in
the brake fluid and therefore flagging the ABS warning.
The suggestion to give the ABS a thorough work out by
forcing it to operate through heavy braking on a loose
surface may clear that muck from the valve(s) but if you
already have an ‘ABS’ warning, the ABS is inhibited so of
course it will not operate.
A complete change of brake fluid is always a good idea - you
will probably need to bleed a couple of litres through the
four bleed points to do any good.
In the meanwhile, check again the cleanliness of the
connectors, particularly the 2-way black connector with the
Red/yellow and Black/slate wires at the ABS main valve, the
7-way grey connector at the ABS valve block and the 55-way
black connector at the ABS ECU.
The fact that in swapping the ABS ECUs temporarily ‘cured’
the problem suggests to me that it is likely to be an
electrical connectivity problem rather than an actual
mechanical failure.–
The original message included these comments:
yes its says fail not fault. sorry
I have changed ecu. had speed sensors cleaned and checked. had all
electrical and relays checked by an auto electrician.
the accumalator charges and after 30 pushes on the brake pedal it
hardens up.
she hardly has been used over the last five years and has not had
a brake fluid change could this cause the problem or do you think
the first port of call would be to change the abs pump
–
Bryan N, now Jag-less, but fun while it lasted.
Cambridgeshire, United Kingdom
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i have a 1992 xj40 soverign 3.2 24v
i have an abs light on. I have done a blink test and the only
fault code to come up is 21 which is main valve.
i have had an auto electrician look at it and everything is
good on the whole system.
i have drained and flushed the brake fluid and fitted new front
pads.
i have also fitted another mastercylinder and main valve and
abs ecu.
we have bled the system as per the manual bleeding procedure.
but still abs light is on and the pump starts working as soon
as u touch the brakes.
anyone any ideas what could the problem be and how can u get
the abs light of is it just a case of driving over 20mph.
thank you in advance this problem is driving me insan–
kayla72
st helens, United Kingdom
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In reply to a message from kayla72 sent Sun 7 Jun 2015:
I guess you have measured all sensors?–
The original message included these comments:
I have an abs light on. I have done a blink test and the only
–
XocjX
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In reply to a message from XocjX sent Tue 9 Jun 2015:
thanks for reply yes checked all the sensors and they are good.
does anyone know do you have to pressure bleed the system as I
have bled back brakes 5 times and still getting small air bubbles–
kayla72
st helens, United Kingdom
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In reply to a message from kayla72 sent Sun 7 Jun 2015:
help help
hi does anyone know if the accumulator ball if faulty generates a
blink code fault.
i am at the end of my tether at the moment I have been told that
blink code 21 is the main valve but I have replaced this but it
seems as if things are going from bad to worse with my brakes.
cheers stuart–
The original message included these comments:
fault code to come up is 21 which is main valve.
I have drained and flushed the brake fluid and fitted new front
pads.
we have bled the system as per the manual bleeding procedure.
but still abs light is on and the pump starts working as soon
as u touch the brakes.
–
kayla72
st helens, United Kingdom
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In reply to a message from kayla72 sent Fri 19 Jun 2015:
A failed accumulator sphere will not generate at Teves blink
code 21 although I believe a wiring fault in the pressure
sensor warning switches in the combined pressure warning
switch (CPWS) will generate a code 61. However, in my
experience, if there is any ABS fault even if the main
valve is good, the blink test will still generate a code 21
as well as the real failure code and the code 21 will not
disappear until the actual fault is rectified and the car is
driven at over 19 mph.
BUT, if the fault is in an inlet or outlet valve which in
itself should generate either a code 22, 23, 24, 25, 26, or
27, the system will not show that code because it will only
show the first code in that group - i.e the code 21.
Forgetting the Teves blink test for a minute, if the pump
starts on the first application of the brakes then you have
a Teves brake pressure problem which may well be the
accumulator or in the CPWS. You say you see the ‘ABS’
warning light. Do you not also see the ‘BRAKE’ warning light?
If when either or both of those lights are illuminated, have
you pressed the VCM button? What does the LCD screen say? If
it says ‘FAIL’ then you have an accumulator pressure fault
and/or you are low on brake fluid.
You mention that you have bled the brakes.
Are you using the correct rear brake bleeding procedure for
a Teves equipped '92 car?
-
With ignition OFF, discharge the brake accumulator by
operating the brake pedal 20 + times until the pedal ‘goes
hard’. -
Top up the brake fluid reservoir to approximately 2 mm
below the bottom of the filler neck -
Open the bleed nipple on one of the rear calipers and fit
a clear plastic tube to direct the brake fluid in to a
suitable container -
Fully depress the brake pedal and hold it down
-
Switch on the ignition and wait a MINIMUM of 15 seconds
until the brake fluid flows freely from the bleed nipple
with no evidence of trapped air bubbles -
Close the bleed nipple and slowly release the brake pedal.
-
Switch off the ignition.
-
Repeat for the opposite side rear brake.
-
Ensure that the brake fluid level does not drop below 10
mm of the ‘MAX’ mark on the side of the reservoir during
this entire procedure.
Report back and I or someone will try to help further.–
The original message included these comments:
help help
hi does anyone know if the accumulator ball if faulty generates a
blink code fault.
I am at the end of my tether at the moment I have been told that
blink code 21 is the main valve but I have replaced this but it
seems as if things are going from bad to worse with my brakes.
–
Bryan N, now Jag-less, but fun while it lasted.
Cambridgeshire, United Kingdom
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In reply to a message from Bryan N sent Fri 19 Jun 2015:
Stuart,
I meant to add that, obviously, if you have no pressure in
the accumulator sphere then you will not be able to
successfully bleed the rear brakes.–
The original message included these comments:
- Switch on the ignition and wait a MINIMUM of 15 seconds
until the brake fluid flows freely from the bleed nipple
with no evidence of trapped air bubbles
–
Bryan N, now Jag-less, but fun while it lasted.
Cambridgeshire, United Kingdom
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In reply to a message from Bryan N sent Fri 19 Jun 2015:
hi bryan thank you for reply I am slowly going bald with this
problem.
in answer to your question the abs light is on and never goes
off.
the fluid is new and is topped up to the max.
we are getting lots of fluid out the back but with very small
bubbles.(looks like fizzy pop).
we have bled it via manual, foot on brake pedal, ignition on,
undo bleed screw. shut bleed screw and release the pedal.
took the car for an illegal drive and tested the brakes
stamping on them makes it skid.
hope this helps a bit more
and again thank you for your help want to get car back on road
as she is beautiful but not the same if you cant drive her–
kayla72
st helens, United Kingdom
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In reply to a message from Bryan N sent Fri 19 Jun 2015:
hi bryan thank you for reply I am slowly going bald with this
problem.
in answer to your question the abs light is on and never goes
off.
the fluid is new and is topped up to the max.
we are getting lots of fluid out the back but with very small
bubbles.(looks like fizzy pop).
we have bled it via manual, foot on brake pedal, ignition on,
undo bleed screw. shut bleed screw and release the pedal.
took the car for an illegal drive and tested the brakes
stamping on them makes it skid.
hope this helps a bit more
and again thank you for your help want to get car back on road
as she is beautiful but not the same if you cant drive her–
kayla72
st helens, United Kingdom
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In reply to a message from kayla72 sent Sat 20 Jun 2015:
sorry bryan forgot to add only get red brake warning light after
about 9 pushes of the brake pedal.
and yes vcm displays fail
cheers stuart–
kayla72
st helens, United Kingdom
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In reply to a message from kayla72 sent Sat 20 Jun 2015:
Stuart,
OK, let’s go back to square one. Not sure if we covered this
previously but try this test and report back:-
Teves Brake Boost / ABS pump performance
Typically, if my car had been sitting unused so that any
residual pressure in the accumulator had long since
dissipated,(or with the ignition off, the brakes were
applied more than 20 times) on turning on the ignition
(without starting the engine), the pump motor would run (do
you hear it on your car?), the ABS light would extinguish
after 32 seconds, the ‘BRAKE’ light would extinguish after
35 seconds and the pump would stop after 42 seconds. How
does your car compare?
With the ignition still on, the pump on my car would
re-start on the second application of the brake and run for
3 seconds to recharge the accumulator.
How about on your car?
Then, with the ignition switched off, it usually took about
30 applications of the brake before the pedal �went hard’
when servo assistance was lost. This is the ‘acid test’. It
may be easier (or more readily apparent) to notice when the
brake pedal ‘goes hard’ if instead of operating the brake
with your foot, you use the palm of your hand.
Report back for further assistance.–
The original message included these comments:
sorry bryan forgot to add only get red brake warning light after
about 9 pushes of the brake pedal.
and yes vcm displays fail
–
Bryan N, now Jag-less, but fun while it lasted.
Cambridgeshire, United Kingdom
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In reply to a message from kayla72 sent Sat 20 Jun 2015:
Stuart,
Another thought.
You say that ‘‘we have bled it via manual’’.
Does that mean that you have a copy of the factory Service
Manual for your car? If so, check section 70-17 through
70-20 wherein you will see 30 different electrical test on
the ABS system. You would be particularly interested in
tests 28, 29 & 30 which concentrate on fluid level and
pressure sensors/switches (CPWS) which sound as if they may
be at the root of your problem.–
The original message included these comments:
we have bled it via manual, foot on brake pedal, ignition on,
–
Bryan N, now Jag-less, but fun while it lasted.
Cambridgeshire, United Kingdom
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In reply to a message from Bryan N sent Sat 20 Jun 2015:
bryan
hope this makes sense
turned ignition on to first point (no lights on dash board
second point on ignition is when all dashboard lights come on
and miles are shown… hope this is making sense) in first
position pump runs for about 30 seconds.
turned ignition to second point pumps takes about 35 seconds to
go off no rid light. touched brake pedal and pump comes on
again for 7 seconds but still no red light but abs is on.
turned off ignition
33 pumps on the brake pedal and it starts hardening up
slightly.
start the car, engine running, pump runs for 1 min and vcm says
‘‘fail’’ red light is on. after 1 min pump stops and red light
goes of press brake and pump runs for 5 seconds abs light on no
red light.
pump pedal for nine times slowely red light comes on pump is
already running after first press and runs for five seconds.
after this everytime the brake pedal is touched pump runs for
two seconds–
The original message included these comments:
residual pressure in the accumulator had long since
dissipated,(or with the ignition off, the brakes were
applied more than 20 times) on turning on the ignition
(without starting the engine), the pump motor would run (do
you hear it on your car?), the ABS light would extinguish
after 32 seconds, the ‘BRAKE’ light would extinguish after
35 seconds and the pump would stop after 42 seconds. How
–
kayla72
st helens, United Kingdom
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