Hello all,
I drive a 2006 XJ Vanden Plas with 130K miles on it.
It's been running great, with no fault lights, until this morning when, suddenly, I got a "Gear Box Fault, ABS Unavailable, DSC Unavailable and a Cruise Control Unavailable" message all at once.
Is anyone familiar with this?

Thanks,
Mark H.
Westerville, Ohio, USA

 

Others may come in with more suggestions, but my kneejerk advice is check the battery. They get VERY grouchy when the battery is iffy.

Good luck!

 

And the default response: check the ground points, most importantly the one behind the headlamps

 

Classic low voltage messages. And by low voltage it's sometimes a tenth of a volt low. If you get "Cannot release parkbrake" you might find yourself stuck somewhere! DAMHIK...

If you run it long enough to ensure a good battery charge, you'll probably need to reset it by pulling the battery cables (both of them, negative first,) touching them together for a few seconds, and then reconnecting the battery (positive first.) The negative first when removing and positive first when connecting is so you can't create a dead short if your wrench touches the body while removing the positive terminal. You will NOT like it if that happens!!

Anyway, the reset clears those errors out, assuming the battery is actually strong enough the next time you started the car. Mine's not my daily driver, and if I'm leaving it parked for more than a couple of days I'll put it on a maintainer to avoid the low voltage.

The grounds mentioned in a previous post should also be checked for corrosion. As they corrode, they increase resistance and thus reduce voltage, and the resistance creates heat which just makes the corrosion worse.

 

All the items mentioned in your post need wheel speed data.

Scan the vehicle for possible wheel sensor failure.

 

Type your question into the Search Box at the top of this Forum or into Google Search and you will get a million replies telling you that it is very likely your battery!

 

My '08 Vanden Plas did the same thing once. Quite the WTF moment. I calmed down, replaced the battery (although the car was starting well even in sub-zero weather), and voilà - all the error messages disappeared.

 

Battery

 

Hi Yellow Bandit,
I went out and got a new battery and that was not it. But I needed a new battery anyway so thanks for causing me to look into that.

I then took it for a scan at the local auto parts store and they said that the right, rear wheel speed sensor was bad.

I'll take it in tomorrow and see if that's the problem.
Thanks,
Mark H.

 

Hi meiron1,
I think you might have hit on it.
I went out and got a new battery and that was not the problem.
So I took it for a scan at the local auto parts store and the scan said, "Replace wheel speed sensor(s)." Specifically, "Primary DTC - Rear Right wheel speed sensor."
I'll take it in tomorrow and see if that's the problem.
Many thanks,
Mark H.

 

A real good fresh battery should have around 12.6 Volt.
check yours in a couple of days right before start. Right after start and a minute running.
the alternator sends up to 14.6 volt ,then drops usually to about 13.6 Volt.
wheel speed sensor is giving all info needed for abs esc transmission and cruise controle.
while replacing those check the gap all round between sensor and reluctor ring ( no dent ,dirt, scratches, rust underneath causing bump)
had the ssme story but after 150mile driving suddenly appearing light on dash Dsc unavailabe . Switching off and on wich made it disappear. Then after third attempt while driving at 50mph a heavy clunk in the transmission dsc, transmission fault, cruise controle and abs showing up on the dash.
had a dent in the ring rear right side

 

Sounds good. I don't know if you DIY, but this is pretty simple to change out. I THINK I did it once.

 

If I remember correctly; when replacing sensor, make sure it is oriented correctly. It is possible to insert and clip in the sensor 180 degrees "off", which will result in false error signals. Don't ask me how I know that .

 

Take a wire brush and clean any rust off the ABS tone/reluctor ring teeth while you have the wheel off to replace the speed sensor.

 

In my personal experience, if I have a battery that is on the way out, , the engine simply won't start (I will not get any error messages at all). Actually, I would definitely check the earth grounds inside the trunk (boot) first, and perhaps behind the headlights).

 

Thanks all!
The problem turned out to be the right, rear wheel speed sensor. I had a new one put in ($355 USD) and all the faults, errors and engine light went away. woohoo!
This forum was incredibly helpful and got me to the solution much faster than I thought it would be.
Much appreciated,
Mark H.
Westerville, OH, USA

 

I had faults similar to the OP, but not wheel-speed-related. I'd get cruise unavailable, cannot set parkbrake (or cannot release parkbrak, if it was set,) although the car cranked and started fine. After running a while (and thus charging) I could stop, do a reset with the cables, and all was fine. It all went away with a new battery. Even though I had no trouble starting, all those faults would happen if the car sat even just 2 days.

 

Thank you, took your advice on mine and the leads coming into the pasgr front headlight area were both horrible. Bottom one completely hanging there and broke off, upper one broke off when I tugged on it. Damn, what a POS.

 

Very similar with problem my car is developing, only 'the cristmass tree" comes while driving; either on highway (happened twice in two weeks) or in city, also happaned twice.
DTC: no DTC according to Carsoft. Once it set TPC code, but it is a red herring: I was pushing on accellerator while cranking engine.
Battery cranks engine with no efforts, judging by that along I would never suspect battery, but USB/Voltage meter in cigarette lighter says there is only 11.8V while cranking and 13.8-14.0 at highway speed.
Car sists on trickle charger, just in case I have to use it before Friday.
New battery goes in this coming Friday. I will bring old one with me to store so they can load tested it.
I will post results after this weekend.

 

I just checked the battery which I thought was good and it says it's bad. So that's the next thing on the list. Argh