Hi
I am fitting an XJR motor to a XJC, and I cannot identify this part, it is in the middle of the throttle cable, and seems to be a motor ?

The car does not have cruise control, I have absolutely

no idea what this is !

 

Its a RHD car and the unit is near the ABS unit

 

That's your traction control actuator.

In case you didn't know it detests wheel spin via the ABS wheel speed sensors and physically starts closing the throttle until wheel spins stops. You may have felt it operating on low traction surfaces

Cheers
DD

 

Doug, I know that "detests" was a typo and you meant "detects", but what you wrote is actually much more accurate! That's what makes the X300 such a horrible car to drive in the winter, as the slightest bit of slip it shuts off the power with a vengeance.

There are a few hills that it was impossible for me to drive up in the winter with traction control on, whereas in my previous Series III V12 car stormed up them like it was a 4x4. Whenever it was slippery I had to change my route to work to avoid any hills, as the X300 would just stall out on no power, not wheelslip.

I think Jaguar was just ticking boxes, and they needed to have traction control in the brochure. A limited slip diff would have been a much better choice than this particular traction control system.

 

I agree with all of the above, and would throw in that it rather neutralises the benefit of a limited slip diff too. Just as well they fitted a switch to allow you to turn it off.... The switch is marked "Trac" and is on the right hand wing of the instrument pack. A warning lamp illuminates in the instrument pack to remind you traction control is off.

 

Thanks Guys,

As with many things.... obvious when explained !

I guess I wont be fitting this to my XJC then !

I always thought that traction control retarded the ignition to 'depower' the engine and put the brake on the spinning wheel. But I have no experience of these systems,

Well off to make a throttle cable then ;-)

 

I agree, worse than useless on snow/ice. I always turned mine off in those conditions.

Cheers
DD

 

On some cars, yes, retard timing. Or fuel supply cut off. Different manufacturers uses different methods.

The X300 service manual is vague on whether the traction control system will apply any braking force. As I recall it is mentioned once but not fully explained. I never had any sensation of the brakes being applied.

Other than the ice/snow problem mentioned above I thought is was a good system.

When I originally bought my XJR the system was a bit over active, which was annoying at times. Later, though, it was much less so. This ties in, IMHO, with cable adjustment and stretched cables

Cheers
DD

 

Despite having a limited slip diff on my XJR, turning the traction control off never seemed to make much difference. When she is out of traction on one wheel, the other wheel always to be similarly afflicted. Not a big problem where I live, but not difficult to imagine this was not universally the case!