Hello,

I've searched the forum, and other forums, for posts describing a problem similar to mine, but to no avail (nothing really matches my situation).

My X308 (117 000 kms -- yeah, I'm in Europe) sometimes fails to start, i.e., it cranks normally (normal noise/speed), but does not start.
After a couple seconds I get messages "ASC, ABS", and "FAILSAFE ENGINE MODE".
I have an OBD reader, but there is nothing to read even when these messages cycle on the dashboard display.

So, some days -- mornings or afternoons, whatever the weather is --, it won't start. Few hours later, it starts normally.
If it started one day, then I can drive and stop it, it WILL always restart. If it sits overnight, problem may occur again.

I thought it would be the fuel pump, but I hear its buzzing sound each time I turn the key to position 2, so it should be fine (?).
Might be the spark plugs, but when the engine runs, it is perfectly stable. Throttle body is quite dirty, but seems to operate fine (I cleaned some dirt without removing it completely yet).

I tried to disconnect the battery, even charged it because it had 12.05V, but no change even with 12.5+.


Now, one "solution" I have found --worked twice, each time I tried it--, is that when it doesn't start, I place the gear selector on N and retry... and it starts.


Does it ring a bell to anyone ?


Regards,

 

Stretched shifter cable?

 

Could be a dieing transmission selector sensor on the right hand side of the tranny. If it starts in N but not in P it can be that...

Or the P position inside the car isn't right. Does the stick make a been noise when you try to move it out of P with the engine off and no foot on the brake?.

 

The gearshift interlock should inhibit cranking completely. Moving to neutral does suggest slector cable adjustment.

The error messages are probably the result of cranking with a failed start partially discharging the battery. These cars are very sensitive to battery state of charge.

However, as it will start again throughout the day once you do get it started, my thoughts turn to a faulty temperature sender unit. If the ECU is receiving an intermittent or out-of-range signal from the temperature sender, this could be preventing the normal enrichment required for starting from cold.

Graham

 

Thanks for the insight ; I wouldn't have thought of these items.

@Daim : the stick doesn't make any noise in that position, actually won't budge at all.

I'm having an oil change tomorrow (I confess that I haven't done one in 15 months and 10k kms, and the oil looks a bit dirty..) ; I'll ask the mechanic to plug in his own ODB reader, possibly it will find something that mine fails to pick.

Hopefully he will also be able to check the selector cable and the temperature sensor.

I'll try to update the post with further information/resolution.. might help other people in the future.

 

Hello,

Just a quick follow-up: an oil change was performed on Wednesday, and I changed the air filter as well.

Nothing else, and the car now seems to start normally with the gearbox stick on P.. so, I don't know.

The mechanic also checked the OBD codes and found nothing, but possibly he can't get the Jaguar-specific codes (since the seat memory and alarm do not work, I'm guessing some module is busted and the Jaguar WDS software might pick it up).

Apart from that, I asked him to verify the gearbox oil, which seems to be clean and red, so that's a good news.
Bad news : the front shock absorbers (dampers? not sure what the correct term is) need to be changed, he says... that would be 2200+ €. Haha, nope.

Not really urgent though, so I'll see to get them on ebay or something and change them myself.


Anyway: not much to add to the original issue for now... If the issue persists and I find what's wrong exactly, I'll update the thread.

 

Hi all,

About a month later, the problem is unfortunately still present after all. Most of the time, the car won't start in P, and I need to switch to N.

Recently however, something new started happening : the gearshift remains stuck in P... when pressing the brake, I can't hear the "click" in the J-gate when the interlock mechanism disengages.
It takes a few tries until it works, actually I noticed that after I leave the foot on the brake for several seconds, eventually the lock disengages (5 to 10s..)

It stresses me a little bit as you can imagine, since if that mechanism is failing (or something else), at some point it will just remain locked.

Could it be the brake switch instead ? Brake lights seem to operate normally, and the switch itself as well...


And of course, both issues might be totally unrelated for what I know..

Any advice on what I might try to identify the faulty part and repair it?


Thanks,

 

Post #4 seems pertinent

 

I have a similar problem... it will every now and then fail to start at the first attempt.. it doesnt even crank... stone dead.. but if that happens it always start at the second attempt..
I also at times have to wait for the guard to let go of the shifter..


The question i beleive is; what the heck is not broken, but itermittently prevents my car from starting??? If something is properly broken it shouldnt suddenly somehow repair it self and function normally a few times.. and then go broken again...


I beleive that the sticky shift stick case is do to some "normal?" agening of a mechanical part.. it should be possible to deal with... the issue is to "get to it"...


The stone dead car at start attempt may.. and this is my humble unsceintific guess, may be due to ageing electronics, especially capacitors. What if the charging times to one or a few capacitors is off, causing the "key check sequence" betwen the electronic boxes to become out of sync?.. just a tiny, tiny bit.. but enough to fail starting the engine... At the second attempt all capacitors are charged.. whatever.. and then the key check sequence is timed right... and the car starts..


/E

 

I couldn't check the temperature sensor yet, I plan on doing that as soon as I can.

However, as per my gearshift stuck in P, I found the reason : faulty brake switch..
I realized that when the interlock mechanism took some time to disengage... the brake lights did that as well after all.
Yes, while driving, too.

I changed the switch and it seems to be ok now.

Most likely, no relation with my start failures however.

Einhead, your problem seems fairly different.... you should open a new thread about it, you'll get more visibility and support I believe.

 

Hi Jackson,

Sorry to join your thread so late. Intermittent no-start conditions are often the result of problems with multiple components or systems. But in your very first post you mentioned that when you checked your battery voltage it was at 12.05V. That indicates a battery that is only 50% charged, so either the battery is failing or it is not being properly charged. Here is a chart showing state-of-charge:




The reason this might be important to your intermittent no-start condition is that if the battery voltage falls below around 10.5V while cranking, the Engine Control Module (ECM) will not trigger the ignition to fire. Testing voltage sag while cranking is difficult for the DIYer because most meters can't react quickly enough to show the true low reading of the sag, but a good auto electrical shop should be able to tell you if your cranking voltage is falling below 11V, and if so, you either need a new battery or to clean your battery power connections and grounds associated with the starting and engine management circuits. You can find the locations of these connections in the Electrical Guide, which you can download here:

Jaguar X308 Electrical Guide 2000

Please keep us informed.

Cheers,

Don

 

Hi Don,

Yes, that was actually one of my first thoughts when it started happening ; especially since it does not seem to hold the charge : after driving for a while it's at 13+V, but on the next morning it is back to 12.0-something.

I might have to replace it soon in any case.

However, I fail to see how it would explain why it starts everytime in N... actually I fail to imagine any reason for this to happen

 

Your battery is shot. It should hold a minimum of 12.5-12.6V.


I don't know if this is true in the ZF 5HP25 transmission, but it seems possible that in Park the transmission internal components could offer slightly more resistance than when in Neutral, causing greater voltage sag when in Park. Hopefully one of our automatic transmission experts may chime in to either confirm or contradict this theory.

Another possibility is that if you've cranked in Park without starting, you may have slightly warmed the engine oil and battery so that when you shift to Neutral there is slightly less cranking resistance to cause the battery voltage to sag.

Personally I would replace the battery - Jags are notorious for needing strong, healthy batteries.

Cheers,

Don

 

Hi Don,

Yes, that makes sense.

Sometimes however, I directly switch to Neutral without trying to crank in Park first ; and there wasn't one occasion in which it didn't start immediately.
Of course, there is no way to know whether it would have started as well in P.

Nevertheless, I'll follow your advice and replace the battery soon. I'll update the thread accordingly.

Cheers,

 

Won't start in natural or park and when trying gently to take it out of park without key on I get a buzzing/noise. Thanks for the quick reply