Unknown problem

[colindelahoy1990752]

I have a message that has come up on my dashboard that says "DSC Not Available "there are also traction control and brake warning lights on"
My car is a 2003 (53 Plate) XJ6 Saloon Automatic
Has anyone got any idea's what it means?
The car is driving completely normally, and nothing seems to be wrong, except for the messages!

[PaulGover]

Colin,

DSC is "Dynamic Stability Control", which is to stop you losing the back end under excessive throttle (and thereby avoiding "tank slappers" - unlike the later XJ's, the XJS doesn't have DSC, as I know to my cost).

Connecting an OBD reader to the diagnostic port will reveal much more information. Most likely, a failed LH wheel speed sensor, a magnetic gizmo fitted to both back hubs that get speed information from a toothed ring on the half shafts. Without that, it the ECU has no idea how fast the wheels are turning, and hence can't spot if the tyres have lost traction, so it affects both DSC and ABS.

You can manually disable traction control with one of the push buttons by the J-gate gear selector - easy to do if a passenger puts their handbag on the centre console for a moment. That shouldn't give brake warnings though, as far as I recall.

[ptjs1]

Colin,

I have moved your thread to the Electrical section of the appropriate X350 Forum.

Those fault messages on an X350 can also be symptomatic of:

- An engine fault, which then disables other aspects of the drive train to protect them

- A low battery voltage which can cause spurious fault messages

If I were you, I would start by checking battery voltage, prior to starting it up. If it's lower than 12.7, I'd charge it up. I'd also check for which fault codes have been thrown.

Good luck

Paul

[BrianG]

I can say with almost complete certainty that your fault will be caused by a fault in one of the four wheel speed sensors. Over the last 10 years with my car I have replaced three out of these four sensors and always had the same fault messages (plus also 'Cruise Unavailable').

You need to get a decent diagnostic code reader to pinpoint the faulty sensor as this will save time and money. The sensors are relatively inexpensive provided you buy the OEM ones and not Jaguar branded ones (See SNG Barratt web site). The rear ones are very easy to change; the front ones take a bit more time because they are less accessible, being buried at the back of the wheel hub, and the cable from the sensor also has a connector hidden under the plastic wheel arch liner.