Hi all.
on my 2003 XJ8
I have abs and dsc lights on, also ‘dsc inoperative’ message. These are the fault codes as read by a snap on diagnostic. Would appreciate some help on this as there are so many codes its hard to know where to start!C1165 wheel speed sensor rear right input circuit fail

C1175 wheel speed sensor rear left input circuit fail

C1280 yaw rate sensor signal failure

C2778 sensor power supply failure

P1260 security input

P1582 flight recorder data is stored

U1027 SCP(J1850) invalid or missing data engine rpm

U1040 SCP(J1850) invalid or missing data vehicle speed

U1058 SCP(J1850) invalid or missing data vehicle transmission

5200H/20992 undocumented code

 

Replace the wheel speed sensor
It's easy and doesn't cost much
Reset the codes and go from there

 

Thanks for that.
Seems strange that both rear sensors and the yaw rate sensor could all be faulty but I’ll probably try replacing them all for starters. No info from the engine Rpm, vehicle speed and gearbox is a bit of a worry, I’m trying to think of a common fault that would cause all three

 

You could consider clearing all the faults to see which of them come back again before spending a penny?
Would have thought you would flag a CATS System or Suspension fault if those codes are all still present?
Some of the codes could be caused by a battery 'dip' at startup?

 

We cleared them and they all came back. The battery seems fine.

 

Understood, but please keep in mind that the DSC/ABS fault can often be tripped by a battery dipping under starting load?

 

The yellow brake warning light never goes and the dsc light comes back on after driving a short distance.

 

Replace the wheel speed sensor
It's easy and doesn't cost much
Reset the codes and go from there

+1

 

What is the voltage on your battery?
A voltage drop test will tell the condition of the battery.
Just because it starts the car means little.

 

What was the prognosis? I think my parents 2007 XJ8 is having the same issues. Lots of faults coming across.

 

It seems the previous owner was messing about with the JLR SDD software when the battery ran down resulting in at least three different control modules being corrupted. Now they wont talk to the diagnostic so theres no way of resetting them.
I only got it as a cheap project to tinker with, but its going to take way too much time to sort out so unfortunately its got to be sold as is.