Here is some advice from the Jaguar Owners Club Forums, where more tips and fixes are available.
Automatic gearbox issues
When I tried to engage drive to move away, the lever refused to budge from park. I tried various, like turning the engine off and on again, stamping on brake pedal, revving the engine, after about five minutes it responded as normal, and remained normal over a number of stops / starts.
Sounds like the gear selector bolt has worked itself loose. I had the same problem on my 2003 XJ6. You need a new bolt fitted. Fairly straight-forward
There is an electric interlock that prevents you from shifting out of park without pressing the brake. This is a safety feature that most modern automatics have.
If your VDP is like my Stype, then there is a Gearshift Interlock solenoid and not-in-park switch at the J-gate assembly.
Also at the J-gate assembly is a module that receives a CAN data stream.
With the engine running and your foot on the brake, the CAN data stream tells the J-gate assembly that the brake is on and what gear the transmission is in.
When you gently and slightly pull the shifter toward R, the not-in-park switch is closed and sends a signal to the instrument cluster. Eventually, the CAN data stream carries a message to release the gearshift interlock solenoid.
So, where can problems occur?
1. CAN data stream is not getting to the J-gate assembly. If the P for park is illuminated, the data stream is being received and power and GND are present.
2. The switch at the brake pedal is not working. There are two switches, one works the brake lights the other cancels cruise control. Are your brake lights illuminating? You might have to get under the dash with a multimeter to check these.
3. The wiring from the brake switches to wherever is bad.
4. The not-in-park switch is bad. Because you have disassembled the centre console and have access to the J-gate assembly, you should be able to access and test the not-in-park switch. J-gate assembly connector: Pin 1 – 12VDC (green orange) Pin 2 – GND (black) Pin 4 – Not-in-park switch output, GND when closed (yellow)
5. The wiring from the not-in-park switch is bad. See 4. It looks like you could safely short pin 2 and pin 4 of J-gate assembly connector (back probe) as doing so would just bypass the not-in-park switch.
6. The gearshift interlock solenoid is bad. Similar to 4., you should have access to the solenoid. Check voltage across solenoid and resistance through solenoid.
7. The gear position switch inside the transmission is bad.
Parking brake issues
I saw ‘Parkbrake fault’ and the car would not come out of park or move. More than a few on / off cycles and some time later, it eventually released and I drove to my destination a short distance away. On getting back to the car I see “cannot apply parkbrake” message again, but the car is driveable, now officially worried.
The first thing I would try is another battery, or at least disconnect, then reconnect the old one. Low battery causes electronic havoc in XJs and XFs and can cause lots of warnings messages to appear. The wiring was chafing as suspected and it seems to be in line with the issue being more prevalent when its wet.
Also try this:
1. Switch off the ignition. Disconnect the battery for 30 seconds. Reconnect the battery.
2. Start the engine.
3. Firmly apply and release the foot brake five times.
4. Confirm that the message ˜NOT CALIBRATED” or ˜APPLY FOOT AND PARK BRAKE” is displayed on the instrument cluster message centre. This indicates that the parking brake is in calibration mode.
5. Lightly press the foot brake pedal.
6. Apply the parking brake by using the EB switch.
7. Release the parking brake.
8. Release the foot brake.
9. Confirm that the brake warning lamp is no longer illuminated on the instrument pack and that the ˜NOT CALIBRATED” message is no longer displayed in the message centre.
10. Apply and release the EPB five times to ensure no error is present.
Oil leak will be sump and sleeve common fault on these gearboxes.
2003 XJ6 3.0 SE develops a fault with the boot lock (1) boot will only lock onto first latch and does not pull down fully (like it used to) (2) I can only open it with the key and central locking will not work from remote (car thinks boot is open) (3) I have to lock car with key which operates central locking and sets alarm when I open or close the boot I can hear a motor running for a couple of seconds. When driving the boot open warning is always on.
My 2008 XJ (X358) has done only 16,000 miles and is running fine, except that the driver’s window has a curious fault. Whilst the engine is running and I press the window switch, the window will go all the way down without problem, but sometimes it refuses to go back up. If I continue to pull on the window switch periodically it will, after a short time, go up a little and then stop, and if I repeat the process it may eventually go all the way up. Not much use if it’s raining. However, if I stop and switch-off the engine, then turn the key to position 2 and pull the window switch, it will close without problem. I had the same fault on a Rover Sterling about 5 years ago. It was the switch unit.