Ever since first owning this car, these lights are on as soon as the car started, before driving. One time when starting it was not on, but came on, after driving for 100 yards, after some reading on here, it could not be the sensor?

The battery seems fine, and I believe is newer.

I have read about the ABS control module soldering of the circuit board, but is there something else to look at first?

1997 XK8

 

Without a reader for C codes, you're sort of shooting in the dark, but there is a process of elimination that you can follow. It would be nice to know what year and model you have, but I'm going to assume it's anXK8 and the troubleshooting guide will apply.

ABS Sheet XK8.pdf (application/pdf Object)

If you have cleaned the sensors with no improvement, disconnect the battery, then the big connector to the abs module. Lift the finger grip at the top of the plug to unlock.
The trouble shooting guide will point to which pins connect to the wheel sensors. Measure the resistance of each sensor. You may need to stick a thin piece of wire into the sockets as extensions to use the probes. You do have a multi meter, I hope. The resistance should be 1000- 1040 ohms.
If the sensor circuits check out it's probably the poor solder connections to the abs pump. Below is a pretty good set of pictures explaining how to drill into the case to gain access, or you could cut the case open. There are several repair sources on ebay if you prefer to send it out.

JagRepair.com - Jaguar Repair Information Resource

 

I have not cleaned the sensors as I read in another thread that if the light comes on upon start up, then it cannot be the sensors, if you think I should check anyway, I will. I do not have a multi-meter.

Would it be difficult to take out the ABS control module, drill a hole and check connections?

 

+1 on getting a scantier codes. I had previously tried looking at all options including removing the ABS module to re solder (it was an easy job, didn't need to solder though).

Scan revealed the cables from front wheel sensors were causing the fault, not enough slack at full lock and tugging at connector.

Recently had fault light come on again caused by driver side cable-broken wire, so today took cable out and soldered in some new wires.

Will see how that goes but so far so good!

 

Sensors are probably ok, but a broken cable can throw a C code at startup. If there is a Indy shop in your area it would save a lot of messing around to have it tested. Removing the module is not difficult, but the four torx screws can be difficult. I had to disconnect some of the brake lines, but did not need to bleed the brakes.

 

Mine did this, remove the driver side wheel, remove the 8mm bolt securing the abs sensor, clear the sensor grime off the face of it till you see three silver lines, remove the connector and spray With penetrate oil, let soak a few mins.

Do the same passenger front side.

Plug back in and drive.