[x300] X308 Error code P1226 Mechanical guard sensor

I’ve been having some problems with cruise cutting out which is
often associated with an amber warning ‘‘engine failsafe mode’’ .
Last Thursday I was out and the cruise started playing up along
with the message so I swithced off the cruise and the warning
stayed on until I took my foot off the throttle pedal. Eventually
I get a red ‘‘restricted performance’’ warning which stayed on
whatever I did.

Anyway next day before going anywhere I attached my diagnositc port
to my laptop and checked for errors. All I got was P1226 which
points to the accelerator pedal and mechanical guard postion
sensors which are part of the throttle body.

In the test procedure the manual suggests replacing the TPS
(throttle position sensor), APP (mechanical guard sensor) and FTP
(fuel tank pressure sensor). I’m guessing the throttle body
sensors are the culprits so should get them changed asap.

Are the sensors on the throttle body available or do I have to
replace the whole unit? If so does anyone know the part numbers?

Many thanks
Barrie Dawson
Sydenham, London, England
1998 Sovereign V8 4.0–
String
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In reply to a message from String sent Sun 29 Jul 2012:

Barrie,
I may be wrong here but on a recent episode of Wheeler
Dealers they did an early XK8 which shares its engine with
the X308. On the show they said that the sensors you mention
are NOT available separately and that you have to change the
enite throttle body. The Throttle Body is a readily
available part on Fleabay and for not a lot of money. As
they said on Wheeler Dealers ‘‘its a 30 minute job’’ to change
one over.
Others on here will chip in with advise and tips for your
codes as and when. Plus, you never know, Mike Brewer may
have been spinning us a yarn!

Good luck,

Dom–
The original message included these comments:

In the test procedure the manual suggests replacing the TPS
(throttle position sensor), APP (mechanical guard sensor) and FTP
(fuel tank pressure sensor). I’m guessing the throttle body
sensors are the culprits so should get them changed asap.
Are the sensors on the throttle body available or do I have to
replace the whole unit? If so does anyone know the part numbers?



XJ8 02 Sport …essex, United Kingdom
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In reply to a message from dja sent Sun 29 Jul 2012:

Dom,

Whether or not those parts are available seperately, I think Edd
China actually said that calibration would then be required,
putting the fitting of replacments out of normal scope. Whatever, I
agree that fitting a complete TB is the way to go, but you’d be
lucky to do it in the time quoted as the coolant inlet hose at the
bottom is a bit of a PITA. Also what must be remebered is that many
TB faults do no give any fault codes so no messages does not mean
the new (used) unit is OK if none come up.

I don’t watch much TV but I did make a point of watching that
programmme, just for curiosity if nothing else. As usual, it was
all a bit of a skim and some anomalies made be grin;

Whilst it was claimed that the car went into ‘limp home mode’ after
driving for 20 mins, the camera shot shows a ‘stability Control
Failure’ which has to be an error on the part of the producer or
editor.

When China shuts the boot, the rear numberplate all but drops off -
I hope they fixed that!

The emergency gearshifter release plug was missing, something which
always grates on me.

I only saw that prog. once and I’m sure others will come up with
more anomalies. The length of such a programme must be a severe
limiting factor which is why they never give the full story and
just end up fixing one fault, then doing all the easy stuff (brake
upgrade etc.). Having said all that, there are some damn good tips
included in the series, little gems you have to pick out.

Regards

Steve–
The original message included these comments:

I may be wrong here but on a recent episode of Wheeler
Dealers they did an early XK8 which shares its engine with
the X308. On the show they said that the sensors you mention
are NOT available separately and that you have to change the
enite throttle body. The Throttle Body is a readily
available part on Fleabay and for not a lot of money. As
they said on Wheeler Dealers ‘‘its a 30 minute job’’ to change
one over.
Others on here will chip in with advise and tips for your
codes as and when. Plus, you never know, Mike Brewer may
have been spinning us a yarn!


Jags on gas
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In reply to a message from Jags on gas sent Mon 30 Jul 2012:

Steve, It is true there may be faults with a used replacement that
may not cause error codes but when my 1998 TB is producing a code
P1226 from a sensor which is not replaceable I have to replace the
TB. I believe it to be unwise to fork out for a used item that
could have other problems and I would have to do the work again.

I have found a new genuine Jaguar part C2a1470ek via that famous
auction site for �280 incl of delivery.

I understand there was a repair at Jaguar’s cost for TB’s for which
mine should have been done however on investigation this was not
done. There are a number of faults, stalling, cruise problems
among them that are addressed in that repair. The problem I
reported on this topic was giving failsafe warning every time I
touched the accelerator pedal, a sensor I cannot replace.

Any way part is ordered and when it’s swapped out I’ll let the
forum know the result.

Barrie Dawson
Sydenham, London, England
1998 Sovereign v8 4.0–
The original message included these comments:

putting the fitting of replacments out of normal scope. Whatever, I
agree that fitting a complete TB is the way to go, but you’d be
lucky to do it in the time quoted as the coolant inlet hose at the
bottom is a bit of a PITA. Also what must be remebered is that many
TB faults do no give any fault codes so no messages does not mean
the new (used) unit is OK if none come up.


String
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In reply to a message from String sent Mon 30 Jul 2012:

Barrie,
I think you are most definitely doing the right thing by
buying a new TB. The used ones may well get you out of
trouble for a while but as Steve says, if it could have a
fault that doesn’t throw up a code you won’t know if and
when it fails or even if its good when you fit it. I think
with such parts you are well advised to go for the new item
if you can afford to do so. For peace of mind if nothing
else. And Hell, who said owning a Jag was gonna be cheap
anyway?

Good luck with the part and I will follow your post till
its conclusion.

Dom.–


XJ8 02 Sport …essex, United Kingdom
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In reply to a message from String sent Mon 30 Jul 2012:

Barrie,

You should also get a new gasket, part# NNE 3021AC–
The original message included these comments:

I have found a new genuine Jaguar part C2a1470ek via that famous
auction site for �280 incl of delivery.
Any way part is ordered and when it’s swapped out I’ll let the
forum know the result.
Barrie Dawson
Sydenham, London, England
1998 Sovereign v8 4.0


Gary 4.0V8 http://www.jag-lovers.org/v.htm?1253292792
London, United Kingdom
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In reply to a message from gary breyer sent Mon 30 Jul 2012:

A gleaming new throttle body and gasket have been fitted, I was
quite surprised I only had the bonnet up for 2 hours, job done.
Was a bit tricky getting the clip back onto the lower water hose
though.
Anyway, been for a test run and all seems okay, no random warning
messages every time I touch the accelerator pedal. Set cruise at
30 and it held(don’t have any faster roads close by), no drop outs
when engine in overrun and resume after braking worked just fine.
Will be going for a longer run tomorrow, out to Bluewater so will
have plenty of opportunity to test at all speeds up to 70mph.

So for now it’s �287 well spent (TB and gasket).

Barrie Dawson
Sydenham, London, England
1998 Sovereign V8 4.0–
The original message included these comments:

You should also get a new gasket, part# NNE 3021AC

I have found a new genuine Jaguar part C2a1470ek via that famous
auction site for �280 incl of delivery.
Any way part is ordered and when it’s swapped out I’ll let the
forum know the result.


String
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
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In reply to a message from String sent Fri 10 Aug 2012:

My day trip to Bluewater Shopping Centre a success. I set out to
road test my new TB and was pleased with the results. No stalling
at high speed, no cruise dropping out for no reason, no cruise
dropping out when engine on overrun and no annoying little messages.

What can I say other than money well spent.

Oh and the day at Bluewater, a lovely meal in a very nice French
style restaurant followed by a bit of shopping and a Magners in TGI
Fridays.

Barrie Dawson
Sydenham, London, England
1998 Sovereign V8 4.0–
String
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