I know what the manual says about ‘check engine’ light. I’m
curious if other owners of cars of the XJS 4.0 engine have to deal
with this when there is nothing wrong with the engine. Is this
the ‘quirk’ of these cats? I’m about to head out for about a 1,000
mile trip in two days. Oil pressure is strong. Water temp
normal. No leaks. IN fact this car w/70k miles is immaculate.
What’s your thoughts? Thanks for any help I can get.–
former owner XK140MC fixed head coupe
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Rile sent Tue 15 Apr 2008:
What year is your 4.0? if it doesn’t have an OBD then what is the
fault code displayed? Decipher the code and then address the
problem–
BCTCBOSS
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
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There are many things that will set one of the may
codes on a 4.0 XJS. The later the car the more codes
can be set. I have never counted them… perhaps 100.
Some are of the “STOP the car NOW” type and some allow
you to go home (for a short distance) in “limp home
mode” others seem to have no effect on the car
running.
All are caused by a fixable problem from dirty
connectors to broken components.
Some codes are set (turns the light on) instantly,
some have to occur repeatedly to count past the limit,
some occur after a set sequence has occurred.
My '95 is at 60K and I will not hesitate to go out
now, or any day, for a 1000 mile trip. I have done
this many times. The light has only come on twice in
five years due to minor problems that were fixed with
a little work.— Rile flip@cmspan.net wrote:
I know what the manual says about ‘check engine’
light. I’m
curious if other owners of cars of the XJS 4.0
engine have to deal
with this when there is nothing wrong with the
engine. Is this
the ‘quirk’ of these cats?
In reply to a message from Geoffrey Green sent Tue 15 Apr 2008:
The cat is a l996 and does have the ‘connector’. I haven’t found a
place here in Phoenix yet that sells them, but looking.
Thanks for the response. I think I should run it by the local
Jaguar dealer & see what’s up.–
former owner XK140MC fixed head coupe
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
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In reply to a message from Rile sent Tue 15 Apr 2008:
Auto Zone (no affiliation)will read your code for free on your 96.
That will at least tell you if it something that needs instant
attention or not, takes all of about 3 minutes to have them read it.–
The original message included these comments:
The cat is a l996 and does have the ‘connector’. I haven’t found a
place here in Phoenix yet that sells them, but looking.
Thanks for the response. I think I should run it by the local
Jaguar dealer & see what’s up.
In reply to a message from Power sent Wed 16 Apr 2008:
I went out and purchased a Innova 3100a code reader. All I’ve got
to do is figure out how to get it set up. Anything with
instructions, I’m almost dead in the water Found it at Checkers on
sale for $99.95 after a $30.00 rebate. Noticed Sears also stocks
it. Any other folks using one of these, and are they pretty
reliable?
I was told by prior owner, one way to ‘‘reset’’ the computer, is to
disconnect the battery and wait about 60 seconds. Anyone know if
this really works or not. Another Jag owner said that you have
have to go to a Jag dealership to get the Check Eng. light turned
off without the code reader, and the charge is about $85.00???
Wow. They get you coming & going. Thanks for all the help on
getting on this website. As good as it gets!!!–
former owner XK140MC fixed head coupe
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
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In reply to a message from Rile sent Wed 16 Apr 2008:
The Check Engine light fault code is stored in memory and the Check
Engine light will illuminate at switch on until the memory is
cleared. Disconnecting the battery for a few seconds will clear
the memory. (It will also clear the radio code, if such is fitted
and the computer memory.)
If the fault is transient and lots are, this may be all that’s
needed, but if the fault is still present then the Check Engine
light will come on again, as soon as the fault is detected.
I had a 92 4.0 that would randonly illuminate FF23 at odd
intervals. There was no real fault, the dealership confirmed on
more than one occasion, and disconnecting the battery always
cleared the sytem. It eventually went away when I put a
replacement Lambda sensor in the glove box, leaving the old one in
place.–
The original message included these comments:
I was told by prior owner, one way to ‘‘reset’’ the computer, is to
disconnect the battery and wait about 60 seconds. Anyone know if
this really works or not. Another Jag owner said that you have
have to go to a Jag dealership to get the Check Eng. light turned
Perhaps that symbiosis only applies to RHD cars Rather like
carrying a spare CPS in the boot to prevent Crankshaft Position Sensor
failure.
George Balthrop, Clifton, VA USA
85 & 89 XJ-S Coupes; 89 XJ40 VDP-----Original Message-----
From: almcl al.mclean@blueyonder.co.uk
I had a 92 4.0 that would randonly illuminate FF23 at odd
intervals. There was no real fault, the dealership confirmed on
more than one occasion, and disconnecting the battery always
cleared the sytem. It eventually went away when I put a
replacement Lambda sensor in the glove box, leaving the old one in
place.
// please trim quoted text to context only
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
10
almcl wrote:
I had a 92 4.0 that would randonly illuminate FF23 at odd
intervals… It eventually went away when I put a replacement Lambda sensor
in the glove box, leaving the old one in place.
In reply to a message from Geoffrey Green sent Tue 15 Apr 2008:
I didn’t know that some come on after a set sequence, or
counting past some limit. I have a 94 6.0 V12 and it appears
only to have an OBD I socket in the boot (trunk) and I have
yet to find someone that can read it. My light comes on at
random intervals - switch off the engine and its gone until
the next time. It only seems to happen when driving at
motorway speeds, say once every 20 trips. The engine doesn’t
seem to be affected and on asking my mechanic he said ‘‘Well
it’s not on now’’! I tend to ignore it now if it comes on,
since it is always gone next time I start up again. If I
knew where to start looking I might have a fiddle but last
time I touched a cable on the car I lost half the dash
lights and the radio.–
The original message included these comments:
Some are of the ‘‘STOP the car NOW’’ type and some allow
you to go home (for a short distance) in ‘‘limp home
mode’’ others seem to have no effect on the car
running.
Some codes are set (turns the light on) instantly,
some have to occur repeatedly to count past the limit,
some occur after a set sequence has occurred.
In reply to a message from fiffaro sent Mon 21 Apr 2008:
Jonathan,
Next time the check engine light comes on, shut the car
down, then just turn the key to the ON position. The code(s)
will flash/display on the LCD clock on the dash. Jaguar had
a PDU diagnostic machine for reading, clearing and
diagnosing faults. Most of them were sold to independent
Jaguar mechanics after the dealers stopped working on our cars.–
The original message included these comments:
counting past some limit. I have a 94 6.0 V12 and it appears
yet to find someone that can read it. My light comes on at
In reply to a message from equiprx sent Mon 21 Apr 2008:
Thanks equiprx, however, I’m one of the ones with an analogue
clock.–
The original message included these comments:
Next time the check engine light comes on, shut the car
down, then just turn the key to the ON position. The code(s)
will flash/display on the LCD clock on the dash. Jaguar had
In reply to a message from fiffaro sent Tue 22 Apr 2008:
I have the same situation (analogue clock) and my check engine
light stays on all the time. While the light coming on has not
negatively affect the operation of the vehicle I did notice that
the lights on my sunvisors have started working since the ‘check
engine’ light came on. Also the oil pressure gage is dead but
occasionally resurects to tell me all is well with the oil
pressure. First chance off from work I’ll be cleaning contacts etc.–
The original message included these comments:
In reply to a message from equiprx sent Mon 21 Apr 2008:
Rather like