2003 Jaguar s-type 4.2 -- Engine fault, parking brake fault and DSL fault- when slowing down and goes into limp mode. Have to shut off engine and restart. does this every couple of months or so and it is usually close to needing an oil change

run fault code and check for TCM problem. The limp mode is also for engine faults.

hi your issue is that your car which starts with petrol then switchies over to lpg for which youll already know ,but the problem lies within the cylindar heads as it can only be 1 of 3 things =1, your valve seals are worn excessively due to the lpg as that runs at a higher heat density which stretches the valves which in turn causes then to wear and that reduces the power ie lack off,as it puts the ecu into limp mode (safe to protect your engine) as its a common fault on ALL lpg conversions.as that is also the knock on effect with your master servo (brakes).as i fix approx 3/4 a month.
hope this help's to clarify what is wrong ok

I had the same thing here, I paid lots of money to find out what is the problem, mechanics played with my poor car damaged everything they can to stop it from running, but when I found out that when I changed the battery on my own, with a turkish manufactured battery of 100 A big battery, not even the fault stopped appearing but all the car was boosted in performance, Dsc not available and Park Brake is all related to the level of electricity running the parts of car was screaming back to you, change my battery, all parts of Jaguar runs on electricity, main computer now runs faster, no delay on screen, and now Dsc not available once ignited doesn't appear anymore, remember that once car is reset by battery change, you need to apply brake and boot (step on brak and hold park brak lever up at the same time with pressing computer button on stearing whisk for like 10 sec until you see on screen AVE back again), and bypass radio lock by pressing on the three buttons, mem and the right combination with >>, and you're set

you need to have the car scanned for freeze frame data code reading to see what happened at the time of the limp mode...Let me say that at times after heavy rain or even if you wet the fire wall near the throttle body, that can also cause the limp mode coupled with brake, dcs,and gear box fault and engine fault lights etc...You can actually do a hard reset yourself by disconnecting the neg battery terminal for 30 min..Let the car run and take it for a drive to make sure the shift points arent jerky.But have the car scanned and let me know what code comes up.

MOST TIME LIMP MODE MEAN ECM FAILING IF YOU CANT ERASE OLD CODE AND REPROGRAM ECM. AND IT CANT RELEARN NEW PART ECM HAS A MEMORY FAULT.

Replace the throttle position\body sensor...part cost$175 +/-

how do i fix or reset this fault
Engine system fault,park brake faultengine system fault, park brake fault & dsc not avilable

4 recalls so far. http://www.motortrend.com/cars/2003/jaguar/s_type/recalls/index.html

unhook the battery for about 15 minutes, that will reset the computer. if you have an anti-theft radio. make sure you know the code first.

one of tha abs and traction sensors has blown

Hi,you might try just to disconect your battery for five minutes ,this will reset your computer and may solve the problem, Good Luck