As MShedden said, the copy of the K309 service action document I have (attached below) does seem to exclude N. American cars. I hadn't noticed that when it first came up here.

Unless there's a revision we haven't seen, I wonder why US dealers are doing the reflash. It does include all V6 and V8 VINs (K00001 to K29970).

 

Here is a photo of the service record confirming the update

 

I suppose that its possible that Jaguar NA re-issues these TSBs under its own name for legal/contractual/warranty reasons.

 

EK993,

Thanks, that resolves the "mystery."

Your service invoice refers to "K309NAS1", with an issue date later than the original K309, which excluded N. America. Obviously, the NA refers to us.

 

So this is the new norm and is inevitably going to happen to all of us?!?!?

I thought I read somewhere that the customer cannot refuse these types of updates???

I would be so enraged if my R's sound decreased b/c of these continuing updates! But I imagine those of us with late build MY 2016 R (12/15) have the latest software--so then why don't our cars sound muted? Unless they are and we just can't decipher the difference...

 

I'm with Kief on this...
Larry

 

So am I.

 

Kief, question - if you are doing say 10pmh with very light steady throttle application, in dynamic / sport and you lift off - does your car burble / pop / crack? Previous to the service my car did - the pops and cracks were embarrassing to a degree. Now - absolutely nothing, silence.

Only when I boot it up to say 4 or 5k with aggressive throttle followed by a snap lift off do I get any pops and cracks.

 

The sounds the car makes in dynamic and sport is the voice of God, and I'm still taking it easy on her with only 491 miles (thanks Jag App!) on her...but the next time I drive her (next week) I will need to make myself cognizant of your example above and get back to you.

For further clarification, how warm should the car be when I conduct this experiment: cold, mid, warm/hot and flat surface?

 

Flat surface, 10mph, steady throttle with very light throttle application, lift off.

From a cold start the cracks, pops and bangs were very loud and lots of them - sounded like a firecracker show on overdrive!

Once engine had warmed there were still plenty of pops and bangs, however they are a little mellowed out and not as loud / violent sounding - like you were viewing the firecracker show from a little distance away instead of being in the center of it !

Now - I just have silence.

 

Maybe none of this applies to the V6, but at no time even before the 309 update have I had an embarrassing level of backfiring, and the sound was no different pre- or post-309. (It could be that my 6/15 build already had the muted sound, and only the O2 parameters were adjusted). However, there was a noticeable increase in exhaust sound level (during acceleration) and backfire (on decel) after the tune.

 

10 mph I get negligible snap, crackle, and pop in dynamic/sport, just a little burble. Need more rpm for me to snap.
Larry

 

Piecing together various accounts here, I think it's plausible that original MY '14s and perhaps cars into the '15 MY run were programmed for more "snap, crackle, and pop." My '14 is very vocal in all modes and erupts at both high and low rpm, both cold and warm. I'd hate to lose that.

If my recollection is accurate, it's owner's of early cars that are reporting before and after K309 differences. Later year owners seem to be reporting no difference.

 

I don't get many pops on decel at higher revs until it's warmed up, or so it seems.

 

Same here on my MY16 S. Perhaps there's something in Foosh's comment re: 14/15 cars being inherently more lairy before it was dialled back for the 16.

Can't say I noticed this but I'd only had the car 2 months before getting the 309 update (and hadn't long run it in so experience of high RPM driving was limited at that point) so perhaps I just didn't notice as I wasn't fully 'tuned in' to the car in those earlier days of ownership.

 

That makes sense; my 2014 V8S has copious amounts of "snap, crackle and pop". OTOH, though I like the sound of the exhaust, I could do without the noices on over-run and decel, especially since/if they are contrived and not an actual functional noise of the engine.

I'm still wondering if this is all software generated (i.e. by injecting small amounts of fuel after the combustion event to create "mini backfires" in the exhaust, or if the "vacuum amplifier" in the cabin that someone mentioned is responsible for producing much of it.


Dave

 

Yes, that's absolutely what causes it, and it was intentionally programmed that way. JLR made a big deal of that in their early marketing materials as part of the car's character, and all the early reviews picked it up and wrote about it.

 

Someone needs to save an ECU image for 'POP' posterity in the hope that a tuner can put back that which has been taken away...

 

Maybe that programming was to gain lots of press exposure and build a hype around the car - but was far from optimal from a reliability or engine management / emissions perspective.

Once the world had heard and read about the initial reports, brand recognition had been built, they felt they could tone down the overun pops etc for more efficiency / reliability or whatever?

Just speculation....

 

Thanks. So is there any OTHER device other than the adding of fuel and exhaust baffles used to create or amplify the exhaust sounds?

In any case, I appreciate that people like the sound and that owner's have the right to be upset if a reflash changes the sound (especially if it's all done on the sly) but for myself, I like the exhaust tone under power but honestly I'd be happier if the contrived pops on decel disappeared...

Cheers,
Dave