Hi all, My friend has an XK8 4LTR 1999. There was the codes that came up as for the two knock sensors, and also the front two o2 sensors, these sensors this week were changed for new. As prior to the above being changed, the car was at idle and then the revs were increased by itself then drop back down. After taking the car for a run it went into limp mode and enough to get it back home. This then when above installed new was doing the same.
These codes were then erased from his hand held OBD11 Diagnostic tool, then it was taken to a Jaguar specialist on Thursday 24th Sept for a diagnostic test and drove great with no problems about a 60 mile round trip. Jaguar found a fault being P1647 (HEATED OXYGEN SENSOR CONTROL MODULE BANK 2 OPEN/SHORTED) and C1095 (PUMP MOTOR CURCUIT FAILURE) that was on the print out it said on its Diagnotic Machine and deleted any old codes that maybe. Sadly, as my friend took it out the same day after returning home, its all the same again as described above. Also the Fuel filter was changed a week before the sensors were changed and there was no difference.
He would be so greatful of any info you may have to try and find out what the problems are to then be corrected.
Just to say that the Engine Check Light does not come up on the dashboard or ever have.
Please do your very best. Thank you.

 

My first guess would be a wiring problem considering the O2 short code. Could also be an internal ECM problem or water problem (has it been raining?). These kind of problems can be a pain to figure out.

If memory serves c1095 is the ABS pump and probably is not related to going into limp.

As with any jag electrical problem, the first question is how is your battery?

 

Hi Carl,
I had a very difficult time understanding your post. The sentences run on and lack punctuation. Maybe if you slow down a little it would be easier to follow.

Do I understand correctly that the engine is surging at idle, that is, speeding up and slowing down continuously? Then, when driven it goes into limp mode but no codes are stored? Have you tried reading the codes while it is being driven and in limp mode?

The C1095 is indeed the abs pump pin problem. There are several threads here covering removal of the module and re-soldering the pins or look in the DIY Sticky near the top of the page.

I'm sure if you can explain a little more clearly what the problems are others will make an effort to help.

 

Thank you, the battery thats on his jag is brand new just before I submitted the post. However, it starts ok in the morning and when it gets up to temperature it then has the warning lights that says, ABS/TRACTION CONTROL, took it for a drive for about 5mins and then goes into limp mode. Then switched of engine for about 10mins and then continue to drive again. The ABS Pump dont seem to work as when the engines started, as putting his hand over the pump there is no feeling there of it rotating or pulsing as such, its been said that the Module of this pump is a common failure of a dry solder joint, this is what sends the live connection to that pump. There is so many posts saying the same problem other people have on here and other posts. Thank you again.

 

Hi all, My friends XK8, 1999 4.0 LTR today has been Diagnosed with this. The Throttle Body and the ABS Module have been sent away for repair. There is as most are aware that within the throttle body is a sensor, and the module has a circuit board, these now are being looked at to recondition them or repair them as such. Hopefully this will end the problems that he have had over the last few months. I will inform you on or after Wed 14th 2015 when he gets it back. Bye for now.

 

My friend has had good news on his XK8 1999 4.0 LTR, the module for his ABS Pump has been repaired. However, the bad news is that the Throttle body has to be done being new at a price of £1.500, or a reconditioned one at whatever the price is at this time, his engine is a AJ27 as I think the earlier cars has a AJ26 meaning the throttle body is different. The mechanic said its one being a Non air and the other being an air Throttle body, whatever this meanes.
Help and advise will be very appriciated. Thank you.

 

Many members have had them rebuilt by ASI with good results:

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