after fixing manifold air leaks and forward O2 sensor I got to a point where the only issue was fans running, I have been in contact with turbo (Chris) previously and carried out tests as per his instruction cheers Chris, I did replace the module with new one from China, my original issue was one day after a drive both fans were running full and flattening battery with or without engine running hot or cold ign or not, replaced module fans then ran when ign turned on and went off after key removed for few seconds, I could live with that, then everything started working properly on some days fans would only come on when temp demanded them or A/C turned on but then would revert to being on all time with ign on.
yesterday the temp gauge which has never gone above mid-range suddenly went to almost red, I pulled over killed engine and left ign on, no fans operating hoses fit to burst with pressure, I had no tools so had to wait to cool down, my theory I would get home (not far) in leaps and stop to cool when needed but when I pulled away the temp went back to normal and I could hear the fans running so carried on to get home.
today I checked connections, battery and earths etc. no codes no leaks, no coolant loss, belts all good everything looked ok so I left ODBC on to keep track of temp and started car, let it run to temp, gauge rose gradually to normal but ODBCII saw temp continue to rise to 106degrees and no fans cut in not even when I turned on A/C so I turned off engine to cool, when I can get my big hands near enough I will check values again but all these problems seem to me like electrical gremlins very hit and miss and intermittent and a real headache.
I don't want to start using bodges to install additional manually controlled fans to reduce temp I would rather have her work the way she is meant too.
as usual guys any help appreciated.
OK she has cooled enough to work on, I checked the blue/white wire and getting 0.12v not exactly cold engine yet though so I replaced the module with second one I bought at same time from China (no disrespect but they were cheap so got two) volts still 0.10v and now am back to where I started? almost, fans coming on full with ign, speed reduces when A/C turned on, I can at least now run her again and see if things settle or go wrong over next few days.
I hate electrical gremlins so now Iam wondering why I put a deposit on a new tesla model 3 lol
A few days later fans still start full with ign (happy to put up with that) after a drive noticed they werent running, temp started to climb again, (luckily I changed to Evans waterless the ODBC said temp was approaching 115 degrees so I killed the engine to allow to cool.
so this clears the fan module so now I am still thinking gremlin (poor electrical connection somewhere) I am suspecting the ECU has intermittent issues maybe, so guys, where is it can I test it or any ideas on price of replacement,

yesterday I was doing the wire wiggle testing method where I try to see if I can make the problem go away or repeat with moving engine bay harness around (sometimes this will show poor connections) in this case it did nothing, I started the car from cold after ODBC code clearing not that there were any.
engine started normally, no fans running, after a few minutes fan kicked in for about 5 seconds then off and it did this regularly as it should to mentain temp, after about 15 minutes idling the fans stopped cutting in and the temp began to rise over 100 degrees again getting to 115 before I shut her down, I was tryint to remove the harness from ECU near bulkhead to check for water ingress, corrosion etc but it has tamperproof screw which I need to get around.
the way it stands is this is very hit and misss it could be temp related as in when the car get to temp an electrical contact has expanded to a point it becomes unreliable and the problem I am having starts again.
thinking of getting a mobile sparks in to test it but if anyone has experienced similar gremlins please let me know.

 

Common Jaguar ECU Faults - ECU Testing

Specialized ECU Repair, Replacement, & Testing - Restore or Exchange your Electronic Control Unit (ECU)


https://moduleexperts.com/modules/jaguar-ecm-repair/

 

Hi Dell, thanks for the post, these links don't have my model listed so I will continue to work on it cheers

 

yesterday I was doing the wire wiggle testing method where I try to see if I can make the problem go away or repeat with moving engine bay harness around (sometimes this will show poor connections) in this case it did nothing, I started the car from cold after ODBC code clearing not that there were any.
engine started normally, no fans running, after a few minutes fan kicked in for about 5 seconds then off and it did this regularly as it should to mentain temp, after about 15 minutes idling the fans stopped cutting in and the temp began to rise over 100 degrees again getting to 115 before I shut her down, I was tryint to remove the harness from ECU near bulkhead to check for water ingress, corrosion etc but it has tamperproof screw which I need to get around.
the way it stands is this is very hit and misss it could be temp related as in when the car get to temp an electrical contact has expanded to a point it becomes unreliable and the problem I am having starts again.
thinking of getting a mobile sparks in to test it but if anyone has experienced similar gremlins please let me know.