About every 3 or 4 start just ABS light and sometimes light and both data screen warnings. If there when starts never goes away when driving. If not there when starts, never comes on with driving. If on and shut down, when restart goes away.
Codes: C1155, front left wheel speed sensor input circuit failure ; and C1145 front right wheel speed sensor input circuit failure.
Possible but highly unlikely two would fail at the same time, so thinking module. This is my 2002 XJ8 LS swap. I have the ABS unit from my 2001 XJR parts car. Assuming the same.

 

My X305 suffered from loose front brake splash shields -- both sides, a couple years apart. The swarf from the jangling sheet metal magnetically collected on the ABS sensors which would sometimes trigger the ABS/TRAC lights.

 

Sticker shows already replaced or repaired,

 

Abs in these cars are stupidously sensitive to battery voltage. It only needs to drop to 10volts or so when starter is spinning and you have abs light on with message. This usually goes away when engine is running and voltage goes up. Because you have wheel sensor issues I quess that you have one issue and one feature at the same time.
Having both front sensors faulty at the same time is unlikely. But possible. Delete codes and llook what code comes up first.

 

There's a short wiring harness from the sensor to the main car loom which can fail. I'd be surprised if both sides had failed together though. Easy enough to replace, it only runs up the top suspension arm & plugs in on the inner wing/chassis rail.

 

I'll check those for connectivity. Will then check plugs on inner wings to module plug. If good, I have the spare ABS module.
The Workshop Manual directions include using special tool (stick) and bleed left side brakes when changing ABS pump. Don't understand why. @motorcarman or any other true Jag mechanic?
Today driving and only ABS warning light on at startup. Went away after a few miles.

 

How odd, I just pressure bled mine when I changed the fluid & it's worked on both x308s I've owned.

 

@ pcolapacker:
I was just checking, if I had posted something about that on the forum, but I could not find anything.
I thought that I did have the exact same issue on my X308 - but now I think it was on my X-Type, but then again - I think now the following:

I did have the ABS light on & off issue on the X-Type, and the solution was that one of the many pins inside of the big blue connector to the ABS-module (in this case it was the pin with one of the cables from the front right speed sensor) did not make proper contact with it's opposing pin. I managed to replace that one tiny pin, and the issue was solved.

And I did have the ABS light on & off issue on the X308, and the solution was that the 2 solder points inside of the ABS module, where the power supply comes in) had "cold welds" (= cracked solder points). I read your module has a sticker saying, it is fixed already, but that does not mean that it is fixed for eternity now. The issue with those solder points is explained here:

 

Replaced the entire ABS unit from my 2001 XJR parts car into my 2002 XJ8 LS swap. ABS was working in XJR. Before ABS module codes were: C1155, front left wheel speed sensor input circuit failure; and C1145 front right wheel speed sensor input circuit failure. Those are gone and now have U2500 CAN bus error. On dash, ABS light on, brake light on, low break fluid message (it's full) and incorrect part fitted message. Have done hard reset. Both pumps were MNF 5920 AD and both modules were LNF2210AD. Before did anything, I checked resistance at all sensors and all sensor to unit wiring. All the same. Ideas?

 

try using IDS “brakes” configuration to reinitialize the module. if it doesn’t work that’s a problem with your swap

 

@motorcarman graciously offered to intialize and preventively resoder modules from 2002 XJ8 and 2001 XJR. Installed and both still return "incorrected part fitted." Motorcarman advised install into my 2002 XK8. Did and no issue, so modules fine and problem somwhere else. He suggested check for power at pins. I'll also check for faulty pins as sugguested by @Peter_of_Australia

 

Spend today chasing the problem. First switched wheel speed sensors from a Jag with no ABS/TRAC issues. Did all four in case two were bad. Problem persisted. Then checked the 3 positive inputs to the control module connector. Voltage good. Then checked grounds at module. No ground. Figured out ground not connected to body. Ground wire had popped back out of sight. I think what happened is the module was bad which @motorcarman fixed. When I removed the module to send to him I took off the ground nuts to have room to get my ratchet in and only reattached 2 of the three wires. This is why incorrect part fitted didn’t pop up until reinstalled.