3.0L engine. 41K miles. Garage kept.
History- 2004- No start-flashing lights/alarm. Towed to dealer. Dead battery. 2010- No start in garage. Starter/engine engaged while cranking. Towed to Repair shop--- Started quickly off the truck. No trouble found.
2010 Again- No start in garage again. Starter/engine engaged again while cranking. Towed to shop again. Started immediately again.
Stayed at Jag Dealer Shop for 5 days, cranking/driving>> No problems found. A "Ghost" not welcome in my wife's car.
No "coughing/spitting" while cranking. No reaction at all, like no spark??
Local dealer no help at all. Sometimes it cranks, sometimes, not.
Appreciate some advice on where to go next, besides the trade-in route??

 

It may just be a language problem (I'm in England) but please explain "Starter/engine engaged while cranking."

Also, how often is the car used? What is the longest it sits unused at a stretch?

It may have a dying battery (stirred up when towed) or poor ground ("fixed" by towing) or fuel pump or fuel filter or indeed any of a few other problems.

When was the last time the fuel filter was changed?

 

With the key turned to the Start position,The starter always engages, the engine is spinning, but no start. No sputtering, coughing, nothing. Battery is new. The car has 41K miles and is driven 2 or 3 times a week. It sits as much as a week between uses. Both shops checked for proper grounding. Fuel filter/pump have never been replaced. If it was a fuel problem, wouldn't the engine at least sputter or misfire during starting? (like a car with a faulty carburetor in old times)
Could it be ignition coil. Have heard some discussion about Jag and coil failures. It just acts like there is no spark. Also, when the car does start, even with cold engine, it starts very, very quickly.
Thanks for your help. Trying hard to avoid trading it in.

 

With your symptoms I would be suspicious of the PATS (Passive Anti Theft System)?? What does the red light in the center of the dash board do when the car does not start?? Any flashing? Have you replaced/reprogrammed any keys or have any aftermarket stuff installed? Like remote start or more alarm stuff??

With the engine cranking freely I think your battery is good but still consider this because the S Type is very sensitive to battery condition.

Since the car has COP's all 6 would have to be bad and then they all magically start working? Most likely not.
.
.
.

 

It really can't be anything there's multiple of, so rule out coils & plugs.

How can they check for proper grounding unless they do it at your house when it's a no start? (Answer: they can't.)

PATS could be it. When it won't start, with key in position II (so, not cranking), watch the light for about 2-3 mins and note any flashes.

There are many interlocks such as the ignition switch itself, a known failure.

At that age it should have had the fuel filter replaced. Cheap and quite easy DIY.

If you try to out-guess the fault, good luck!!

 

Now that you mention it, the car failed to start, or even try about 3 months ago. The red alarm dash light was flashing with the key in the number 2 position, and several of the indicator lights in the dash display normally on at that point were off. Flashing/strange lights stayed on even after the key was removed. Battery dead the next morning. I suspected battery, and replaced it. Did not work. Repair shop suggested that I use the spare key that came with the car (path memory loss??). It worked with both keys. The new cranking problem followed this. Also lately, the trunk lock refuses to release while the car is unlocked; must use the key itself in the trunk lock.
If it is the PATS system at fault, how complex is the fix? And, shouldn't the Service Department at the dealership be able to diagnose it, even if is is temporarily cranking?
Again, thank you for the help. I am beginning to feel better about this.

 

Diagnosing can be hard!

A few have reported a chafed wire on your age & engine size. Rear of engine there's a bracket, I think at the top. Sorry to be hazy but I have a different car. Someone may recall where the bracket is or Search may find the messages. You'll need a decent light and inspect very carefully.

If there was a less intermittent fault yes you'd have codes for it. With what you're suffering, maybe codes or maybe not. It's sounding very like bad connection/wiring somewhere.

 

Yes the dealership should be able to help with the PATS. They might be better off to just wipe and reprogram all your keys again just to make sure everything is correct. I would also put new batteries in all the key fobs. Again just in case.

Post back what the red PATS light is doing when you have your problem. There is a sensor in the ignition switch that might be causing trouble too.
.
.
.

 

Clubairth.....my 01jag won't start my alarm light flashes code 1 blink 3 blinks

 

I think that's the same as code B1600 (see codes PDF in JTIS) and basically means key not recognised. Try another key

 

The sensor ring located at the ignition could have moved, try putting one key into ignition and turn on, then use other key to 'wave' it around the dash area by the ignition and see if you find an area that will deactivate the immobilizer. Imagine your other key as a 'magicwand' at this time....you just need to get the transponder inside the key, close enough to penetrate the 'zone' where it will deactivate.

I have installed these 'secret zones' in other areas for other drivers.

Example, under carpet on floor by driver seat. Driver would get in and wave transponder by the carpet to deactivate the system for start up. If you didnt know where this 'zone' was you were screwed, and it added massive theft protection to the whole concept with this style of install.