Hi All,

I’ve been looking to purchase a 5L XKR, but have recently come across a nice 2007 XKR Portfolio. One of the features I really would have liked was the adaptive cruise control, which most of the later 5 litre models appear to have.
My question is; has anyone done a retrofit install of adaptive cruise control on a 4.2L XKR and if so, what may be involved?

Cheers;

 

In case no-one has (or they're not reading), you can figure out what would be needed from the (free download) workshop manual / electrical guide.

Something like the module, radar sensor, maybe some wiring and at worst a reconfig via OE tool. Sounds doable.

Wreckers (ebay etc) should have the module etc but I think they were rare so may take a while to find.

 

I don't know if anyone has actually done the retrofit, probably not since the dealers weren't allowed to do it.

When I had the nosecone off my 2009 XKR I think I found the unused wiring harness for the sensor, so it could be that the car is pre-wired. The parts catalogue suggests that the cars after VIN B10571 were pre-wired for Adaptive Cruise, but it's not explicitly said.

What you would need is;

Radar sensor for the nose (same unit for all X150's) £1100
Cruise Control Module (4.2 has a different version to 5.0) £170
ABS Modulator assembly (4.2 has a different version to 5.0) £1600
Steering wheel switch assembly (this is the same up to 2012MY) £60
Console switch pack assembly (different for RHD or LHD, diff for 4.2 or 5.0) £80

Those are the UK list prices in GBP, so you can figure out the costs with VAT, GST, import duty, shipping, etc... convert it to AUD and add 30% roughly.

Then you need to fit all the parts, the ABS modulator is behind the left front wing, which you need to unbolt to get access... and it will have to be bled using the SDD diagnostic tool.

And someone will have to take care of the programming to make it work, not a DIY thing, and the dealers aren't allowed to do it either, but I know someone in Melbourne who could....

The cost for all the parts new is considerable. As the sensor is in the nosecone, it's going to be destroyed in a frontal impact, so finding one from a wreck won't be easy. And the ABS modulator is not going to be easy to find either really...

I looked at it for mine, and decided i'd rather spend money on something else...

 

Wow Cambo,
That is a fantastic load of information. I was wondering how you knew so much detail of what is involved as obviously you did the detailed investigation already.

�� I really enjoyed having the adaptive cruise control in my BMW, but at those sort of costs, I think I can learn to live without it. Small price to pay for a nice Portfolio, I guess?

Cheers;

 

My 2007 has ACC. Here's the sensor and associated harness:



That's a seriously expensive option for a toy I've only used once.

Graham

 

Yeah that looks like the harness in mine Graham, just hanging there not plugged in to anything.

 

Mine has ACC, a few points below.

The good:

• Two thumbwheels on both sides of the steering wheel; symmetry!

• It is admittedly convenient at times, mostly at lower speeds.

The bad:

• If you have ACC, you only have ACC. There is no ordinary cruise control; the adaptive feature cannot be deactivated.

• ACC will not work when it's snowing, and will tell you the sensor is obstructed. Thus, no cruise control at all until the front is clear of snow.

• If someone switches lanes too close in front of you, it may engage in a fairly panicky-feeling braking after a short delay.

• I've heard that in a bend on a highway, a car in front of you on the other lane may trigger the ACC into braking. I haven't experienced this, though.

• While the car informs me of a vehicle on my lane when the gap is about 7 seconds, the maximum gap you can set is 2.2 seconds, which for my taste is too short at highway speeds. More so if it's rainy/wintery.

• ACC drives like a teenager in an Audi; it gets unnecessarily close to the car in front, then brakes relatively hard to increase the gap. WHY? Is there an intimidation setting that I've missed?

All in all, it is nice from time to time, but in my opinion it's not very relaxing. I feel like I'm constantly supervising it, as though I must be prepared to intervene when necessary, sometimes pre-emptively.

I'm also a bit worried about the car using its brakes rather than engine braking when slowing down, as this presumably also turnes on the brake lights, and I'll look like an idiot who cannot drive in a fluid manner.

Before you set your mind on an expensive retrofit project, try to test-drive a car (an XF will do probably?) that has ACC.

 

There's a wonderful section in the Owner's Handbook description of the ACC:

If the ACC system predicts that its maximum braking level will not be sufficient, then an audible warning will sound while the ACC continues to brake. DRIVER INTERVENE will be displayed on the message centre. The driver should take IMMEDIATE action.

Here's the scenario:
1. system detects maximum braking won't prevent a collision with the vehicle in front
2. you hear the warning sound
3. you look down at the message centre
4. you then take IMMEDIATE action

The handbook doesn't go on to describe what IMMEDIATE action. Presumably call an ambulance and a tow truck .....

Perhaps I'm being cynical but I do think the overcrowded roads in the UK are unsuitable for this kind of 'driver aid'.

Graham

 

​​​​​​
When I first got my XKR, I was dubious at best of the ACC. So, a friend and I went out to a deserted desert road with walkee talkies to play around with it, him being the lead car. I was able to induce the driver intervention alarm and it gives you ample time to look down, look up, decide whether to swerve or hit the brakes, and then do so. But then again, that was under somewhat controlled conditions. Be prepared for a heavy pedal if you ever get into this situation, though.

 

Weird, man. I find that my MAX gap is WAY too huge, and the MIN gap is STILL too huge. Well over two seconds, and at that distance people nearly ALWAYS pull into that gap and go slow.
The first time I had someone pull into my lane too close in front and my car hit the brakes I was NOT expecting that, and I thought something broke somewhere. It took me WAY off-guard.

 

This:
If someone switches lanes too close in front of you, it may engage in a fairly panicky-feeling braking after a short delay.

I had in my XJ SV8 and it was a pain in high traffic. No matter your speed, someone is always darting in and out of lanes. When they cut in front of you, your vehicle slows down, which in turn motivates someone else to cut you off and slow you down even more. As your "adaptiveness settings" keep you a specific distance from the car in front, you continue to slow down and speed up but not as fast as everyone behind you wants. I ended up not liking it for this reason.

Ideal would be normal cruise with emergency stop imo.

 

Yeah, in fairly busy areas it kind of sucks.... BUT in long stretches of open highway during a long trip it is FANTASTIC.
It should be switchable.

 

That is a great description. My '07 4.2 XKR used to do this as well but my '10 XKR is a lot smoother so I wonder if there is a difference in hardware or firmware between the two or whether it can be better calibrated.

Judging by the light on the dash the '07 could see the car in front from quite a long way away but it just seemed to be totally surprised when it actually caught up with it.

 

"The driver can chose between four gap settings, 1, 1.4, 1.8 and 2.2 seconds." - X150 Service Manual

Personally, I can't imagine maintaining a 1 second gap to the car in front of me. I'd feel too nervous, being aware that if they were to fully hit the brakes for whatever reason, I couldn't stop in time. I think ACC is too slow to react to be of any help there.
A lot of the time I drive without ACC and maintain a gap of 3-4 seconds instead, and if someone wants to move into that gap, they're more than welcome. I couldn't care less; can't even remember the last time someone moved over to my lane in front of me and slowed down.

That's interesting to hear! Also an apt description; the car tells you there's a car far ahead, then drives up to it and suddenly hits the brakes like "WOAH"...

Now that I look at JEPC, there are only two sensors for the XK, and the latter one (C2P12024) supersedes the older (XR851912).

However, there are many many adaptive speed control modules:
B00379-B00755: C2P4719 (superseded)
B00756-B20074: C2P11473
B20075-B30299: C2P15674
B30300-B32752: C2P17580
B32753-> :C2P12608

Only the first one is marked as having been superseded, I wonder how's the compatibility with the latter ones. Looking at Jagspares.co.uk however:
C2P4719 > C2P11473 (£60)
C2P15674 > C2P17580 (£203)
C2P12608 > C2D17788 (£282) <- not listed for XK in JEPC though
That last one is nearly twice the weight of the early ones!

"The Adaptive Speed Control module, located on the bottom of the RH (right-hand) A pillar."
I wonder how difficult it is to get to it? I suddenly feel like checking the part number on mine...

 

Weird, man. Maybe (evidently) Jaguar agreed with you that there was not enough interval and increased it (too much) in the later models. My CLOSEST setting is probably the 2.2 second one.

 

Goodness, that sounds like a really poor system. I was expecting it to be the same as the ACC in my BMW which exhibits non of the “Bad”that you mention here. In fact it is absolutely faultless, whereby you set the car space distance (typically 3 to 15 or so car lengths away from the car in front) and it does the rest with absolute perfection.

Don’t know about its operation in heavy snow conditions though, as not really a concern or issue here in Australia. Besides, cruise control of any description should not be used in situations where traction has been compromised in any way (heavy snow or rain).

I guess, by the sounds of it, that the Brits just haven’t managed to get ACC right and I shouldn’t expect it to work with German precision.

Thanks for everyone’s input, I think I’ll give it a miss, as I’ll be seriously disappointed if it had all the issues described here.

 

2.2 seconds is longer than you might think, especially at speed. I had a quick play with a stop watch on the way home from work this evening and my '10 XKR matches the earlier models and what the 5.0L workshop manual says.

You also mentioned in this post that your ACC will bring your car to a halt.

https://www.jaguarforums.com/forum/x...2/#post1573870

I was looking forward to that feature when I got my '10 but mine still cuts out at 18mph as per the documentation so perhaps yours is special?

 

There are three different settings available for the "ACC ECU Market" in the Car Configuration File.

UK-ROW
USA-CAN-MEX-AUS
JAPAN

I don't know what the exact differences are between them, but they are there for a reason, and I have seen the different settings selected in cars from different markets that we have scanned.

 

Mine will stop completely, but then it will immediately start the slow crawl and not rebrake.

 

I wonder why they all don't then because that is far more useful than suddenly releasing the brakes at 18mph and flashing up a message for the driver to take over!

Does anyone else have a 5.0 litre XK where the ACC brings the car to a complete halt?