Hello All.
I have an 04 XJ8, and I am suddenly having intermittent issues. ABS and DSC unavailable, but if I restart it, it goes away. Today the radio started changing stations, but the display stayed the same. Turned off the radio and turned it back on, problem gone.

While driving with the cruise on, the cruise shut off and ABS and DSC lights came on. Parked and restarted after exiting the highway. Again everything reset. Got back on road and went a quarter mile, ABS and DSC lights come on, then the transmission bangs and the Gearbox Fault light comes on. Restart, same result. Everything resets, then ABS and DSC light stay on but not Gearbox fault. Seems like it must be electrical, as it is intermittent. Gearbox fault always follows abs and DSC faults, and then goes away upon restart. Sometimes ok for days or weeks, sometimes just a few minutes. Where should I start? I like to try to fix things myself.....

 

Hi Vince and welcome to the forum. I have moved your post from the XK8/XKR section to the XJ (X350/358) section for your specific model.

When you get a moment, please go to the new member area and post an intro New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum

 

Sounds like Apollo 13 all over again. I'd be concerned first with the bangs and shimmies and then the electrical.

How long since a transmission fluid level check and or change?

 

Thanks SaturnV. The bang was a downshift, I believe. The fluid level is good, and after a restart, operates as normal, only after the ABS and DSC light trips, does anything ever happen. The trans seems to go into limp mode until the car is restarted, which is why I think it is electrical.

 

When the battery is not 100%, these cars start doing funky things like you described. The car will start fine and you won't notice the usual signs of a low battery like in other cars. Maybe replace the battery with a brand new one and hopefully that may eliminates the issues.

 

Vincekal,

I've got some old paperwork where our XJ was tripping the ABS and DSC lamps, I'll see if there is a fix documented. Agree with XJL, how old is your battery?

 

I would have the battery tested first (voltage drop under load).

ABS, DSC and cruise all depend on wheel sensors.

Possible sensor wiring fault or sensor fault.

If you have snow it can block up the reluctor rings too.

 

Things seem to have gone from bad to worse. I checked the battery terminals, which seemed a little dirty. Cleaned them up. Started the car and drove it, and all seemed fine. Came across an icy patch, stepped on the gas and the traction control worked fine. Stepped on the brakes, ABS worked as well. Went another hundred yards or so, and all the lights came back on, then the gearbox fault tripped as well. Now it is resetting on restart and then immediately tripping the gearbox fault, and now the check engine light is on too. Shifts badly out of first, then goes into limp mode. Makes an odd noise, kind of like an old air pump for emissions control on an '80s Dodge. Trans does not slip at all in limp mode. I am in big trouble now? Does disconnecting the battery have any weird affect? I seem to recall having an abs issue this past summer, disconnecting the battery and then having some weird check engine lights, low coolant warning, etc.

 

First place to look is what code faults it is showing. Do you have access to an OBD reader?

 

I don't have a reader, is it the obdII?

 

You will need to have the battery load tested before doing anything else. It sounds like you have a voltage problem.

 

Autozone will check the battery for free and will probably hold a replacement battery in stock.

The XJ8 is a little fussy about ODB2 readers too by all accounts and some are not compatible with the car. A list of the compatible ones are here :

https://www.jaguarforums.com/forum/g...oved-**-33347/

When disconnecting the battery for any period of time you have to reconnect and follow a specific sequence to get the Engine management system working correctly. The sequence is available on the forum. I will see if I can find it.

 

Many excellent suggestions so far. 2 things I would also check.

The alternator, see what voltage you are getting at the battery when the car is running.

Also check the ground points in and around the engine bay for loose or dirty connections.

Agree with most though, get the battery checked first or at least make sure you have a fully charged one in the car.

Hope this helps,

 

+10 for changing the battery

I had even weirder things happening than you. New battery fixed it. $150. I now change the battery every year "just in case"

 

I had most of your gremlins plus my glove box and fuel door would open every time I started the car. I had the battery tested, and they said it was ok, but could use a recharge. Based on my reading on this forum, I decided to just replace the battery. All of my gremlins are gone.

Start with a new battery.

 

Waiting to hear from local shop that has had the car for 24 hrs. Yesterday he said there were 35 trouble codes they were trying to wade through. Wish i would have tried the new battery first. Thanks for the replies. I will post results as soon as known.

 

Ok, so here is the skinny. The shop cleared the codes, and recommended I have the plugs and all 8 coil pack replaced, replace the inertia switch, and replace the throttle body. He cleaned the sensors at the wheels, and I have had no further issues with ABS or DSC lights. I have had no issues at all, having done none of the recommended services. I did replace the battery, as many suggested, and was glad I did, as it was -4F this morning. The car started and stalled twice, but once warmed ran fine. I am thinking of having the throttle body and the inertia switch done, then doing the plugs myself when it warms up. I cannot imagine it needing all coil packs replaced.....thoughts? Thanks again to everyone who gave me advice. Much appreciated!

 

I went through a similar issue and it turned out I needed a new throttle body unit and inertia switch. Fortunately, it was covered under warranty. Hopefully your new battery took car of most of it an cleaning out the throttle body will help as well. Good luck.

 

It's hard to see how all the coils or indeed all the plugs could go bad at once. If it runs apparently OK then I'd get a cheap OBD2 tool with live data and check first for codes then that all sensors (well, those you can figure out!) have plausible values and lastly the fuel trims (LTFTs). They're very affordable tools and work on other cars.

If the plugs are due, I'd change them of course.

You might re-do grounds (I'd say battery terminals but you've done those).

If nothing found, I'd wait and see. You now have the obvious tool should it act up.

 

Don't forget also that you won't be able to rerad any DTC codes until the car has been driven through its drive cycles. This can take upwards of 300 miles ( based on my experience).

Then the codes and issues may resurface, I hope they don't.