I'm under the gun time-wise, will elaborate more later. Basically, the battery has been disconnected for a month or so - shouldn't be a problem but... Insert key, everything works but the car won't crank. Use old diag' trick, set alarm with window down, reach in and turn key on = alarm goes off. O.K>, security issue. Hook up laptop and VCM = key transponder not talking, neither key. Drop panel, coil and harness look o.k. Coil has continuity.

Anyway, I can't seem to be able to lay my hands on any info on the security system. JTIS has no info, even the wiring diagrams are shy about including any info (let alone there's a lot of wires in these cars that are not documented.) I have native scanner (IDS + VCM) but no VMM. Jag apparently has seen fit to not share info below the dealer level, unless there's a manual floating around that someone can post. W/O a VMM this is probably going to take me a while...

UPDATE: Message from IDS - Communications failure with key transponder module.
Run the ISO network integrity test.

O.K., I'd be happy to but I don't have a VMM. Is there a work-around for not having a VMM?


TIA,
Beav

 

Hmmm. My first thought was jiggle the shifter while holding the key, because it sounds like the transmission switch. But maybe it is deeper as you suggest. It doesn't make a whole lot of sense that it would fail that way. though.

 

Yeah, that was my first thought but it's identified though the native scanner.

 

What was the ultimate solution to your no- crank problem??

I'm interested because I also have a 98 convert with similar issues. Car actually is very low miles (34k) and sat unused for several years. Owner put a new battery in it, but the car wouldn't start, or even crank. The dealer played with it for a while, tried to re-program the KTM for the key (and claims it was successful) but still no crank. My symptoms are identical to yours except that when you set the alarm and then turn the key, the alarm doesn't go off.

To me all symptoms point to the key not being recognized by the LTM, no?? My coil checks out good and all....

So what did you end up doing to fix your issue???

 

Forgot to post that I found a cracked fuse (hairline crack, no burnt or curled edges) in the driver's fuse box. No power to KTM so scanner reported it as no communication.

If you roll the window down, set the alarm with the door shut, reach in and turn the ignition on and the alarm doesn't sound the car has recognized the key as valid. That would/should indicate the key, transponder coil, KTM, BPM and Security modules are connected/communicating. However, the KTM also sends the ECM an 'OK to Crank' signal on one wire and a 'Security Acknowledge' to both the BPM & ECM on another. The SA wire leaves the KTM and a splice splits the signal to both. Obviously the signal is making it to the BPM as it then sends the signal on to the Security module.

You may have an issue with the signal not making it past the splice on its way to the ECM, the 'OK to Crank' signal not making it to the ECM, a defective KTM or a defective ECM. Before checking and or condemning any of those items I'd be making certain the starter or starter relay isn't an issue. The dealer should have done that but sometimes people jump onto one thing and forget the basics (witness my forgetting to check all of the fuses first. Yeah, I can admit my mistakes. ;-) I jumped to the conclusion that nothing had happened to cause a fuse to blow but it was just coincidental the the cracked fuse decided to make an appearance when it did. Also, if the dealer said they were able to program the keys that means the computers are talking as one or more modules are inaccessible when they aren't. They won't talk when they have no power, no ground, are defective or the twisted-pair circuitry is broken. Fire up your JTIS and study section 03 in the Electrical Guide. Personally, I'd begin by sticking a test light in terminal 3 of the starter relay and checking for battery voltage. Then I'd check terminal 1 for power with the key in the 'On' position. From there I'd check terminal 2 for a ground when the key is in the 'Start' position. If all that checks out jumper number 3 to number 5 and the starter should work - BE CERTAIN that the car is in 'Park' and the brake is set before doing that. Don't need to read about somebody getting hurt or the car making a dent in your garage wall. If that doesn't work check the continuity of #5 and the small wire at the starter and if it's o.k. the starter needs to come out.

 

Thanks for the reply. I'll check the fusing for the KTM to be sure.

All of the wiring to the starter relay checked out fine. I can get the starter to turn by jumpering the ground side of the starter relay coil at the BPM connector, so the relay, wiring and starter itself are cool. Also, the BPM is getting a signal from the ignition switch (going to ground) when the key is turned, so that is good. So all indications point to the KTM, the key itself, or maybe the exciter coil. I checked continuity on that and got some 27-30 ohm so it may be ok, but I'll swap it with a known good piece from another car and see for sure. Seems like that's a problem area....

The ECM itself may have issues, but I don't think that's the source of the problem. These cars should crank even without an ECM in place as long as the rest of system is good. The ECM is getting the normal 12V from the rotary switch in P and N, so that part is good as well.

Do you maybe have a wiring diagram for the KTM itself?/ What's in the Jag elec guide (starter section) is pretty minimal.....

Thanks

Andrew

 

Does terminal 2 of the starter relay go to ground in the crank position? Obviously it should start but sometimes it doesn't hurt to check to be sure.

If you jumper to crank will the engine start with the key on? That would indicate security acknowledge has passed and probably the BPM can't switch starter relay 'on'. It's sometimes difficult to determine the exact logic and signals produced from a schematic. The KTM has many more wires than what is represented in the schematic - are they necessary? Are they passing through? Are they red herrings?

My current theory is that the coil is o.k. (I believe you got the same resistance value I did) and because the alarm doesn't sound that the challenge has passed verification and the KTM has signalled the BPM that the challenge has passed, otherwise switched ignition voltage/gound present at the BPM would cause the alarm to sound. Next the ignition switch, position 3 (crank, ground signal) should be present at the BPM's FC14-41. Since the challenge has been met the BPM should signal the starter relay and the ECM through FC14-73.

 

BTW, if you need a KTM I've got one for the $40 +shipping that I spent.

 

Terminal 2 of starter relay is not going to ground when the key is turned. The wiring to that terminal and the relay are both good- jumpering that wire to ground at the BPM engages the starter. I did try jumpering the starter with the key in the on position, and the engine will crank but not run. I also did your test with the alarm set and then reach in a turn the key on- the alarm went off. On another identical (running) 98 XK8 I have here, doing that same test with its ignition key disarmed the alarm, so XK8 #1 does not seem to be recognizing the key.


BPM terminal 41 is going to ground when the key is turned to start, so that is good. And I also am getting terminal 7 going to ground when the shifter is in neutral (not in park though). Also, the ECM is getting the correct 12V in P and neutral from the rotary switch.

So all of the wiring is good, and the basic signaling is good.

This may indeed mean that either the exciter coil, the key, or the KTM are not completing the security check, no?

I'll have a check on the power fuse to the KTM- which one is it exactly??

Thanks

Andrew

PS- One other note- a dealer worked on this car just prior to me getting it (trying to fix the no crank, no start problem) and I talked to the tech about what he had done, He claimed the first thing they tried was to reprogram the key to the car and it worked. But the starter still wouldn't turn so they went on to checking the ECM and rotary switch. If the alarm is going off in the above test, I can't see how the KTM actually is recognizing the key, or at least not relaying that info to the BPM. Again, it looks like all indicators point to that system: key-KTM-coil (or maybe the communication between the KTM and BPM)

 

When I tried to access key programming with the IDS it just replied "Communications failure with key transponder module. Run the ISO network integrity test." If the dealer could access "key programming" apparently the KTM has power and is communicating. However, with that being said, I'd still check every single fuse in the car. You just never know what can happen with so many dependencies built in. What frustrated me was the very low amount of info in JTIS. I have no idea if the dealer level has printed material or online info beyond JTIS available. As I've stated before, the JTIS wiring diagrams are woefully incomplete. I know for a fact that the KTM and center switchpack have many more wires than displayed in schematics and I've been through all of them a number of times. Unfortunately, the "Guided Path" diagnostics in the IDS software require the use of the VMM, and I don't have access to one these days.

In regard to which fuse, I don't recall other than it was in the LH fascia box and after I located it through testing I did find that it was listed, in some form or fashion, in the Owner's Manual as including the KTM.

 

p.s. Do you have more than one key?

 

I have just one key. This is a car that sat unused for years at a time. Believe it or not, it is a 98 with just some 33,000 miles on it. The owners just parked it in a garage and got to it from time to time.....

I've checked most of the fuses- so far all good..

One interesting note- there was a rumor that the owner's 18 year old son put a new battery in the car recently and installed it backwards (terminals connected backwards). The dealer figured this zapped the ECM as they could see it on the scanner trying to fire the injectors, but the actual connection to ground for the injector circuits (in the ECM itself) was never completed. I;m wondering if Jaguar's anti theft scheme is similar to GM's in that if security fails, the ECM won't pulse the injectors. The dealer tech said that's not how Jaguar works, but they still couldn't get the cranking to work, so how much do they really know....

Other than the no start issue, everything on the car works perfectly.......

I'm going to swap in a known good exciter coil tomorrow and see if there is any difference. How does the coil come off the ignition cylinder- does it just snap off?

 

Yup, just remove the knee bolster (to access the wiring) and column cowling and it's tabbed in place.

A failing key can cause issues. I have one for my Lincoln that sometimes won't allow the car to start. I swap to another key and it fires right up. Immediately shut it off and use the failing key and it will work for the next few months.

 

We'll see what happens. I ordered 2 more new keys, cut to the VIN code. If this one still doesn't go, we'll try the other 2 when they come in (and get programmed...)

 

I swapped exciter coils from another running 98 and no change. And the original XK8 coil works fine on the other car.

On to the KTM. Where is that located exactly???

Andrew

 

It is truly a PITA. Remove the outer LH a/c register and pry up the duct (deformation occurs.) The two mounting screws are barely visible/accessible. Reach up through the removed knee bolster to handle/remove. I don't think removing the instrument cluster helps but it has been a while since I did it.

My thinking is if the dealer could access 'key programming' the KTM is probably o.k. but that really doesn't mean much. If available, attaching a 'scope to FC22-9, then FC22-17, then FC22-16 and watching for digital 'chatter' to change might be an idea.

 

bump....

Im having a issue starting my car and looking for more info, was this ever resolved

 

I am running into similar sounding issues. Battery is providing power to the car but the wont turn over. I experienced a failure like this a few weeks ago, jump started the car and it's been running fine since. Was out and about yesterday - no issue. Try to start the car this morning and it wouldn't turn over again. Tried the second key - no joy. Tried to jump start (hoping it may just be a slightly drained battery) again but no luck. Any thoughts?

 

Tried the alarm test... The system recognized the key.

 

If the car is recognizing the key, then the key and transponder are good.

Have you checked your starter relay- is it working ???