DSC NOT AVAILABLE ... Help
 

2005 XJR getting an intermittent display of amber and red warning lights that come on and the display switches between DSC NOT AVAILABLE, ENGINE SYSTEM FAULT, and PARK BRAKE FAULT.... when this happens engine reduces power and runs rough.

I can stop car, remove key, open door, this resets condition and then continue driving.
Happened once 6 months ago then again about a month ago and now it has done it 3 times today. My wife driving car so I had her reset and TURN OFF the Driver Stability Control switch by the sifter. On her way home now.

Any suggestions on what to look for???
I have one thought is that the wife about eight months ago hit some high water and it seemed to warp the front rotors. When I apply the brakes I get a light hopping drag from the front and steering wheel shakes very slightly. I will turn rotors and put on new shoes this weekend. they were done about a year ago but I feel that maybe this hopping of brakes might be triggering the ABS sensors causing this DSC warning.

But why am I getting the other warnings too? any clues????

I've moved your question from General Tech Help to X350 forum. This is the place to post technical questions about your model.

Graham

These are classic symptoms of a failing battery, so I'd start by checking there.

The problem may be the earths (grounds) behind the headlights.
They may look ok but I suggest that you carefully dismantle and clean the
the connections.
Be very careful when tightening back the nuts because the recommended torque is
very low at about 3.5NM.
You can search this forum for more experiences by forum members
eg https://www.google.com/search?q=jaguar+x350+bad+earths.

You need to read the codes otherwise you're shooting in the dark.

But the ENGINE SYSTEMS FAULT message is usually a giveaway for a failing throttle position sensor, that message is more serious than "restricted performance"

Read the codes, if you have P2135, then it's the TPS...

What Cambo said. His car is SC, but if you look up those symptoms, you will see that this is CLASSIC TPS issue and the tried and true fix that Jaguar does for this specific set of errors is... New Throttle body. They don't have a TPS to sell you so they replace the whole TB. Yes, and it is every bit as expensive as that sinking feeling tells you, dealers charge $1200-2000 - and I know that rebuilds and used throttle body's are out there, if your handy enough you can swap it out. The worst part of the sway is getting all the hose connections off without breaking any fittings. (the car runs coolant through the throttle body for some crazy reason)

Alternately you can VERY carefully remove the electric connection to the throttle body, use electronic cleaner and tightly re-assemble. Use care with this.

Note: Not a bad idea to check your battery, but I will tell you that this is NOT a low battery cause issue. Yes it can create any number of bizzare error messages, often including Parking Brake and others, but NOT this particular set of errors.

Also - early cars have a TPS on the Throttle Body, that's impossible to source, and tricky to calibrate if you do end up finding one. Later cars (X356 and forward from about mid 2005, chassis number VIN G49701 use a sensor in the accelerator pedal and appear to only have the throttle motor in the throttle body. I have seen people take apart the TPS and clean the little "fingers (look like tiny rakes of metal that gently sweep a semi circle pickup - One worn one will cause this.

That's as much as I can tell you off the top of my head. My 07 Vanden Plas has had a throttle body replaced in 2012 according to service records done this 3x in the 9 months I have had it, and every time I panic, but it has cleared and stayed okay. One of these days it is going to keep failing as yours is doing, and then I will be doing all of this myself. Let us know how you are proceeding and we will try and help!

Some threads on the issue if you haven't seen them yet:

https://www.jaguarforums.com/forum/x...ult-what-9863/
https://www.jaguarforums.com/forum/x...-p1251-126469/
https://www.jaguarforums.com/forum/s...e-fault-51031/

http://www.fixya.com/cars/t7749880-p..._not_available
http://www.fixya.com/cars/t8966589-fix

I had similar issues and it was a dead cell in the battery. Check that out first.

THANKS TO ALL ..... found code P3125 (Throttle/Pedal Position Sensor Switch A/B Voltage Correlation)
What's weird is that this usually triggers at a stop light. Just happened to me and it would not accelerate, so I left engine running and plugged in scanner to find code P3125.
My wife's car so I have kept it the last two days to drive and see. Rebuilt front brakes, turned rotors that were warped and everything is smooth now.

I am very inclined to try to pull and clean the electrical contacts on TPS sensor with Contact cleaner first. Does anyone sell this in an aftermarket part?
And why does this also trigger the "DSC Not Available" and "Park Brake Fault" besides "Engine system Fault"?

Are there any threads on TPS Cleaning that anyone knows of?

After reading these threads I think I will try to just clean and silicone the quick connect plug.
Just have to pull cover and locate throttle body and TPS sensor connector.
Any pics othis anywhere for 2005 XJR?

Cambo .... mine is SC also .... 2005 XJR; and after going through car wash today it tripped the P2135 code after about 5 minutes and after resetting it comes right back on every time I reset.
It was hell getting metal plenum runner off that runs from front to back between inter-cooler but ..... now I can see the throttle body.
With it tucked in at the back of engine next to firewall I can only see two connectors. One for the stepper motor on drivers side and one for the TPS sensor on the passenger side.
This TPS sensor has two screws on it and is removable. It looks similar to the one on my 01-F150 Lightning, but since it is screwed on .... why can't I get an aftermarket replacement unit? Anyone ever done this?

There are aftermarket TPS units available, same one is used on the 2.5/3.0 X-Type, the S-Type petrols from 2003-2005, and the X350 XJ petrols from 2003-2005.

You'll find them on eBay, Amazon, etc... Denso 198500-3300

Here's one https://www.ebay.com/itm/Throttle-Po...5/282324466600 you'll find other listings for the same ones.

You need a 5-point security Torx bit, not the usual 6-point. Don't mess around with the wrong tool, buy/use the correct 5-point bit.

I have never used one of them myself, but seems like others have had success.

Moisture issue with our TPS.

This is what I found to be the fix.

http://www.jaguarforums.com/forum/xj...-fault-209761/

I recently had issues with DSC not available, park brake fault, ABS warnings, and low brake fluid messages and it was a heavily corroded ground point at the front of the car. Mine came off in my hand when I tried to clean them. The other two cleaned up great without breaking. I had to relocate the connections for the broken one to a new ground point. This fixed my problems immediately so I was glad it was a nice easy and cheap fix for me. But you do get similar warnings with TPS and battery failure as well. I tried the cheapest route first to rule them out before spending cash on fixes that may not have worked.