I own a 2003 XJR. All three of these codes came up at the same time. It has happened twice. On both occasions after I turned the engine off and restarted it, the codes went away. Does anyone know what causes them?

 

Any OBD codes thrown at the same time? I know bad power connections inside the ABS module can throw asc/trac faults. Low battery/alt voltage can cause this as well. I don't remember if that will throw the failsafe error as well.

Also possibly slightly dirty wheel speed sensors?

 

What type of driving was it before it happened? ....after a highway drive, after in town driving, were you driving it hard or just casual driving?

 

Very casual driving. 15 MPH. Ironically it was within half a mile of the identical location both times. Slow city driving. No racing or towing.

 

No OBD codes. I am going to take it in Friday but it might not matter if the error messages are not showing anymore.

 

When you say no OBD codes do you mean just P codes checked with a generic code reader? Transmission, ABS and other systems are not covered by P codes.

A weak battery can cause the symptoms you reported, so having the battery load tested and alternator checked would be important, at least to eliminate them as sources of trouble.

 

Agree with advice to check battery. Put it on a charger and get it fully charged. One of the best lessons I have learned on this forum is that when weird, funky stuff starts happening, the battery is always Public Enemy #1. I now keep my '99 XJ8 on a maintenance charger every time I park it at home based on sound advice I received here, and this stuff has stopped happening. Give it a try. It's free and it just might work!

 

Indeed, I've employed the same regimen w/ a NOCO Genius G1100 charger & all of my little gremlins have vanished.

 

Along with the previous suggestions, and in that same format, be sure to check your ground cable lanyard from the battery to the body. I had done a basic check of mine for another issue and it seemed fine. Then later found it to be bad when the issue arose again.

 

Great suggestion for a regular inspection item. I'm curious. Was it galvanic corrosion, rust, frayed strands? What had gone bad, and what do you think caused it?

 

I'm not sure your mechanic will be able to tell much -- I don't believe anything is stored if it did not hold a code.

The car uses what is called a CAN network to operate -- everything is interconnected. If the car looses any inputs it goes into this mode.

The Tbody holds the TPS and PPS both are culprits as is the brake switch. Try pushing the throttle to the floor a bunch of times (engine/ignition off) -- this may clean both the TBody sensors. They are both very sensitive to dirt and sit in a very narrow range all the time -- I had the same issue around 4 years ago .. this eliminated my problem.

Battery -- can't be overstated ... if yours is 5 years old .. replace it. I was getting the shutdown last year.

 

I had all of those things happen on my car. After checking the battery it was the alternator. Had it rebuilt charged the battery. Good for 3 years then had to replace the battery. It was just shy of 5 years old.

 

Interesting, I have a thread started on the same thing and my answer and my research leads to a faulty throttle body yet no one here has mentioned that to Steve W

 

Wow, where'd ya pull that one out of...lol...galvanic, you mean the corrosion created from two different metals in conjunction with battery fluid? No and yes, I don't believe it was that solely, I believe it was from a combination from being in a stagnate position constantly that the metal became brittle from doing its job and dissipating excess energy. Its possible an inferior metal was used and it broke down? There was no fraying, as a matter of fact it looked in quite good condition, seemed pliable enough on the outside.
What happened was the car was dead after shutting it down for a few hours. The interior lights worked on door opening and it dinged when I put the key in. I went to start it and everything went out, even the clock. This being the second time it had done it, I waited about 5 minutes this time listening and checking, then I went into the battery compartment and grabbed the lanyard and it was warm. I knew I had my culprit then.
I went over to my indy to talk to him about it and he had just taken one off of an XK, ironic as that moment was. Bottom line, age got it, like it gets us all.

 

Now why would we want to give him a direct answer, that would be too easy. I have to say I don't recall reading that post JT....dang, I have to catch up

 

+1 on checking the battery and/or alternator voltage
+1 on checking the soldering points for the ABS pump connection inside the ABS module. Had the ASC/TRAC message increasing intermittently (from once/3 month a year ago to daily during the last few weeks before Christmas). It always showed up after driving awhile, especially when the engine compartment got warmed up when stopping at lights or in traffic jams. Since resoldering my issue vanished completely.

Did the issue appear only twice or did you experience it again in the meantime?

 

If you read my post #11 .. I point to the Tbody?

a common problem with the sensor failure .. some of the early non-SC car's have a service action regarding the Tbody replacement. No parts are available --- replacement only. Some have used a rebuilder.

 

I took it to the Jaguar service place. Of course the messages were not showing this time. The only thing they could find was the code b1229. They switched the relays between the AC and TB to see if anything changes.

 

.....and, and, and??? ..ewww, the anticipation:icon_beamm e:

 

I drove it for two days and it hasn't happened again. Eventually I will find out what is actually causing it.