www.jec.org.uk

Hi All,
2002MY - XJ308 - 3.2se
For peace of mind i had the transmission serviced yesterday by Bristol Transmissions which included Autologic scan, Oil, filter and sump gasket change.
All for a reasonable sum(imo) of £180.00 Including parts and oil.
All seems well and the car drove back from Bristol to Gloucester with no problems apparent.
However The autologic scan threw up several fault codes that if possible, i would like any comments from members in order to expand on their interpretation and suggestions of what further work may be required. They are:-

Engine control Module:-
P0172 - BANK A COMBUSTION TOO RICH
P0175 - BANK B COMBUSTION TOO RICH
P1122 - PEDAL POSITION SENSOR CIRCUIT "A" LOW VOLTAGE
P1111 SYSTEM CHECK COMPLETE SINCE LAST MEMORY CLEAR.

Transmission Control Module:-
p1632 - CAN message implausible

ABS:-
C1095 - PUMP MOTOR CIRCUIT FAILURE

Climate Control Module:-
B1969 - COMPRESSOR CLUTCH CONTROL CIRCUIT FAILURE
B1858 - CLIMATE CONTROL PRESSURE SWITCH CIRCUIT FAILURE

To conclude, everything seems to be working ok, The climate control was fine. No warning / engine check lights came on so i am puzzled by the fault code readout.
The car had been into HA Foxes Cheltenham for Fuel pump and Oxygen sensor replacement and Diagnostics scan about 2 weeks ago and all was well at the end of the work.
I wanted to have the gearbox oils changed as result of the well documented transmission problems associated with these cars.
Bristol Transmissions were competent in the transmission service and said the work went well. They have the equipment to remove and replace as much of the old gearbox and torq converter oil as possible. They would not comment on the fault codes other than to say they use the autologic to monitor oil/gearbox temperatures to accertain the correct fluid level for the gearbox.
The Transmission module fault P1632 does concern me and Bristol transmissions have put a disclaimer on the invoice to say they cannot guarantee the condition of the auto transmission.
The car has done 92K now so i suppose i am on borrowed time for this box but being old school i don't believe in sealed for life when it comes to oils and electro mechanical engineering. I have seen enough of electro mechanical clutches in my previous life as a machine tool fitter(many years ago now) to appreciate the value of regular oil and filter changes.
Your thoughts and wisdom please.
Regards
Rod

Rod
As your car is running well and has no apparent problems it is likely the fault log has accumulated
some error codes from transitory/intermittent problems and/or glitches.
If I remember correctly the car software needs to record more than one (3 I think) occurrences of the same fault before the appropriate fault light (MIL) and message is generated.
What I would do is :- Ask your friendly Independant Jag workshop to connect IDS and clear out
the fault log.
Then use the car as normal and don't worry.

Rod,

Well done for getting your transmission fluid and filter replaced. Absolutely necessary!

As regards your fault codes, I'm slightly confused as you said that HA Fox did a diagnostic scan only 2 weeks ago. That would seem to imply 1 of 3 possibilities:

- They cleared all fault codes and these fault codes have, therefore, all been thrown in the last 2 weeks

- They didn't clear the fault codes and these are old codes

- They only scanned the engine ecu codes (and may or may not have cleared them). Many dealers will not necessarily look for non-engine codes unless you say you have a problem. So the other codes could still be old ones that haven't previously been cleared.

As regards the engine codes, P0172 & P0175 are codes that are often thrown with either rich running or with MAF sensor problems. If it's thrown by the MAF, it's often only a dodgy MAF wiring plug connector rather than the MAF itself. Easy for you to check and clean.

If it's rich running, it is possible that this was linked to the replacement of the fuel pump and O2 sensor. So it's possible that these are old uncleared codes. However, I have heard of occurrences where after fixing such problems, the LTFT (long term fuel trim) settings have not been reset, which can then cause the ecu to continue to run the car over-rich and throw the codes (again). I would suggest that you get HA Fox to clear the codes but also ask them about resetting the LTFT so the ecu doesn't get confused, and starts "learning" again.

As regards the P1122 and the P1632, these can be linked together. There was a bulletin issued by Jaguar many years ago which related to throttle adjustment being incorrect and throwing a P1632 code. In addition, the pedal position sensor plug to the main harness can be worn, damaged or just loose and this often causes a P1122 and a P1632 to be thrown.

Jaguar designed the system so that some codes throw the engine MIL (light) and some don't. A code that throws the MIL turns the light on as soon as it sees the code but it also runs on a "3 times valid" cycle. In other words, if the light is illuminated, if the system doesn't "see" the fault for the next 3 times that the engine is started, the MIL will be extinguished. So if the light is off, it hasn't "seen" the code for a while (although it's obviously still stored in memory).

So, as Dave says, you could get all the codes cleared and wait for any problems to return. However, I would ask HA Fox who did the work to clear them for free (as they should have done originally) but ask them to look at / reset the LTFT settings.

Hope that all helps

Good luck

Paul

Hi
Sorry not replied sooner, i seem to have aquired a touch of manflu with an annoying cough that has turned into Bronchitus. Spoke to the Dr and hopefully meds will sort it. Oh the joys of old age.
Thanks all for the informative replies, i think i will try HA Fox again as they were very helpful previously and did state that they removed and reset existing codes. But maybe on engine module only as that is what they were working on originally.
They may question the autologic scan but its worth a phone call to see what they say.
Car is running well and autobox seems fine.
Time now to think about the tensioners, might have a go at those myself as there is a good description of the work with pictures, carried out by Brakebuster some time back
Many thanks again for the info.
Regards
Rod