Hello Jaguarforums members,
I spotted a few threads with the P01603 code but none of the threads fully capture what I am experiencing with my 02' 2.5L X-type so I decided to start one, given what I am experiencing.
I will try to condense as much of this as possible so that this doesn't become a book.

Wanted to mention these two separate issues first, before I explain what is happening as I think they may be related.

1. The ABS and Brake Light have been coming on intermittently for the past few months, namely when the car seems to be driven for a while. When i start it up from siting a while it, the ABS light is off. There hasn't been a code thrown for the ABS and brake light, so I thought that it is probably a sensor going and I'll just replace the front two first and then the back two later.
2. I've experienced a few issues with the ignition barrel in the colder months here in the midwest and used some graphite lock grease to help the wafers/tumblers inside the lock and it seemed to have worked for over a year now. When I would turn the key in the ignition it would say Security Failure and would not turn over. I would take the key out and the alarm/chime (that goes off when the key is in the ignition remained on). I noticed that the little metal flap inside the barrel was not closed so I tapped on it with my finger and it closed and the alarm/chime went off. This has happened a total of 3 times in the past 4 years.

I had some extra time on my hands and was able to get the car up in the air this weekend and look underneath it to see if I would have to take the wheel off to get at those ABS sensors. To my surprise I noticed that the front passenger side Stabilizer Bar Link was broken and just hanging! It seems that it just separated from the bushing/housing. I had noticed that the car was a little sloppy on the steering and also would float right as if I needed an alignment or something. I just had the whole rear suspension changed just over a month ago, plus an alignment and the mechanic never said anything so I am guessing this happened recently (but still, not that happy about it).
I didn't want to drive it with the Stabilizer Bar Link broken, so I got the parts and proceeded to install them. I drove the car up on some ramps, jacked it up a little further to get jack stands under it. Took the wheels off, and proceed to change both the passenger and driver side Stabilizer Bar Links. I then tried to get the ABS sensors off but they were way too rusty so I decided to wait on that thinking that maybe the Bar Links could have had something to do with the sensor since one of them was broke.
So, I was done. I put the car back onto the ramps, jumped in and tried to start it up but the on board display said that there was both a Security Failure and Gearbox Fault. I turned the key off, tried again a couple of times and then decided to check the battery. Tested full (the battery is about a year old at this point). Hooked the battery back up and I then proceeded to manually get the car off the ramps by putting it into to Neutral and pushing it backwards. So the car is now level. Tried to start it again and I was getting only the security Failure error this time (as well as #2 from above). I decided at this point to leave the battery disconnected for a while to try and reset the computer and grabbed my OBDII reader. Hooked the battery up, proceeded to see what I could get on the OBDII. The code that I pulled was the P01603. The car still will not turn over (issue #2 from above happening intermittently). All accessories, AC, lights, locks work normally. The break petal however is very stiff.
I then proceeded to
Swapped out the R8 Relay (for the TCM). The R8 relay had a little dark spot on the side of it. It almost looked like a burn or something.
Took out the ignition Barrel and cleaned the crap out of it. A lot of gunk (and even some lint) came out of it.
Cleaned the battery terminals, positive and negative cable ends that connect to the battery as well as the two ground locations (by the headlight and on the transmission).
Cleaned the starter prongs where the cables hook to it.
Moved the shifter thru the gears to make sure that it was in Park.
Tried my second key.

I also had electrical issues a couple of years ago and ended up replacing the alternator twice but it ended up being the battery cables that were the culprit. So the battery cables are used but recently replaced.

I am thinking that it is the ignition barrel again (still seeing the issue from above) as P01603 can also mean that the ignition was on when the battery was disconnected as I've never had issues with the gearbox before and I've babied this transmission and rear differential with Royal Purple several times over the past 4 year to prevent any type of transmission failure(s).

Silver Lining: I did end up getting those ABS sensors out by the way....they were cemented with corrosion and rust. Took me about 30 minutes for each side. Horrible experience but they're out. Ordered some new ones that should be here later this week.

I disconnected the battery again and left it sitting until I try to get a clue on what to do next.

I'm very frustrated with how this all came about and hoping that someone has some insight. Any help would be greatly appreciated (as always).

Xx_Xtype_xX

 

 

 

 

 

X's seem to eat batteries like cat nip.