Adaptive CC not working. XK 2006

[mike020150]

Adaptive cruise was an extra cost option throughout X150 production. SNGB's listing under 'Information systems and controls' is a straight lift from Jaguar's parts system. That's how Jaguar catalogues it. Mike.

[dyrham663]

The whole thing consists of two main parts, the sensor and the controller.

I think I've been sidetracked into thinking the sensor is at fault when it is actually the controller. The jag part controller (C2P11473) for my early Vin number is no longer available through Jaguar or Barrat. I was trying to find out if the controller for later Vin numbers would work?

Or is the controller from the Range Rover of similar age actually the same part...? If the sensor is according to Roger above.

For example, This Range Rover part diagram from Lithuania on ebay;

https://www.ebay.co.uk/itm/264818762783 ... BMutqi1JFi

Looks very similar to the SNG Barrat diagram of the unavailable Jag part;

https://www.sngbarratt.com/English/#/uk ... 5B27594%5D

Presumably the controller is easier to change than the sensor which needs the bumper removing?

Steve

[mike020150]

To be fair, it's usually the sensor which fails which is why it's important to have the system scanned either on Jaguar's diagnostic system or the Autologic equivalent to pinpoint the guilty culprit, otherwise it can become expensive! There are electronics wizard companies around which are willing to tackle repairing control unit modules. Companies like Bluehawk electronics or BBA Reman, but they don't repair everything and understandably, they tend to concentrate on the higher volume control units.
The Landrover unit may be physically the same unit. However, it's the programming which is the important bit. Without detailed knowledge of the two units, it's impossible to say whether it will work in a different model. Equally, it could be plug n play or, even if it will work, it could require coding to your car on Jaguar diagnostics. Life was easier when all you needed were spanners and a hammer! Mike.

[dyrham663]

Progress... or the plot thickens ....

One of the parting comments from Autoclassico was 'maybe you should check the fuse, its number 15'.

Pah! Thinks I, surely the original garage checked that. Anyway with a few hours to kill and a sunny day and in the interests of 'getting to know the car' as somebody put it, I decide to have a look.

After the usual fight to the death with the scrivets followed by a search for a big crowbar to get the top of the fuse box unclipped I finally was able to check out fuse 15. There was no fuse 15! Obviously removed at some point.

Due to the serendipty of ordering the wrong size bladed fuses for our old Polo a few months back I actually had a10 amp fuse that fitted.

Fired it up and .... The Cruise not available message dissapeared! Yay! But ... whats this ...Warning light 2 that flashes amber to remind the driver that the car is in ACC mode is flashing. The Engine isnt on yet, stays flashing when engine starts. Applying Brake doesnt cancel it. Pressing 'Cancel' results in a pop up message saying 'Cruise not available'. But no permanent warning triangle.

Took it for a round trip few miles to the shops. Light blinks all the time. Brake or Cancel have no effect when car moving either.

So it looks like someone removed the fuse to stop the warning light flashing all the time. Not sure if the original garage knew this or not. I haven't tried to activate Cruise yet as I need to be on a major road and to be honest I would be a bit nervous as it might decide to fall over at that point.

Not sure if this info prompts anymore ideas? In the meantime I have it booked into Swallows in a couple of weeks time for a full diagnostic. At least I wont be charged 2 hours of workshop time to be initially told someone removed the fuse!

Steve

[JimMann]

Hi Steve, this is perhaps a question that should have been asked at the beginning of this thread. Are you 100% positive your car is fitted with Adaptive Cruise Control? The reason for asking now is that the thread has become a little "jumbled" flipping between "ordinary cruise control" and "adaptive cruise control".

The fact that a fuse was removed at sometime in the car's history, would definitively point towards there being an issue that previous owner(s) were not prepared to deal with, but as an aside, the dealer should not have sold the car to you in a condition that did not reflect the true specification (not of merchantable quality), so I would say you still have a case against the selling dealer.

Looking at the issue you now report and working with the assumption that your car DOES have ACC, I can offer the following insight from someone with ACC on my XKR and also ACC on a succession of Range Rover Sports (RRS) from way back. On the odd occasion the ACC on my XKR gives the "Cruise Not Available" message, it is "normally" due to a sensor masking issue, such as a leaf getting stuck to the front of the car. No actions will make ACC turn on, or make any difference and it either comes back on its own (after a while), or the leaf dislodges and hey presto it is available once more.

With your symptoms post the fuse insertion, it seems that you are unable to either engage, or disengage the ACC. You mention warning light 2, do you mean the amber light that comes up / flashes when the ACC (when operating correctly) informs you, the driver, that the car has sensed an obstruction ahead? This is the amber light that looks like a vehicle topped with an arrowhead. If this is a yes, then I would be placing the blame onto the sensor, as opposed to the Control Module.

When driving the car, you intimate that the controls of brake or cancel have no effect on the flashing amber light, but have you tried moving the separation distance by activating the righthand (outermost) thumbwheel on the righthand spoke (side) of the steering wheel?

I would suggest that this should be a next step, along with pressing the "Resume" button when you are on a clear stretch of good road. If the set distance thumbwheel has no impact - you should see a depiction of the car along with 1, 2 or 3 chevrons appear in the dash display, and adjusting the thumbwheel down or up should change the number of chevrons on display - then I would now suspect the Control Module. If pressing "Resume" has no impact, then I would again suspect the Control Module to be at fault, i.e. not accepting commands in both instances.

In regards to the ACC in the RRS, then is is "highly likely" that the parts from a RRS are adaptable to the XK and as there are significantly more (high end) RRS fitted with ACC (it was a standard fit as opposed to an option), then sourcing parts from a breaker of these cars may get you on the road to success, but you will have to remove the nosecone of the XK in order to access the sensor - as you have already found out.

Sorry there is no definitive answer to your problem, but hopefully you are now closer to a solution that is acceptable.

Jim Mann

[dyrham663]

Hi Steve, this is perhaps a question that should have been asked at the beginning of this thread. Are you 100% positive your car is fitted with Adaptive Cruise Control? The reason for asking now is that the thread has become a little "jumbled" flipping between "ordinary cruise control" and "adaptive cruise control".

Yes, it has the radar sensor and the separation distance controller.


With your symptoms post the fuse insertion, it seems that you are unable to either engage, or disengage the ACC. You mention warning light 2, do you mean the amber light that comes up / flashes when the ACC (when operating correctly) informs you, the driver, that the car has sensed an obstruction ahead? This is the amber light that looks like a vehicle topped with an arrowhead. If this is a yes, then I would be placing the blame onto the sensor, as opposed to the Control Module.

No, it is the light that has a car enclosed in lanes with a backward facing arrow. The handbook says it is a reminder that 'follow mode' is enabled. Or maybe it just means ACC is enabled? The light I think you mean is number 16 according to the handbook 'forward alert'

When driving the car, you intimate that the controls of brake or cancel have no effect on the flashing amber light, but have you tried moving the separation distance by activating the righthand (outermost) thumbwheel on the righthand spoke (side) of the steering wheel?

I would suggest that this should be a next step, along with pressing the "Resume" button when you are on a clear stretch of good road. If the set distance thumbwheel has no impact - you should see a depiction of the car along with 1, 2 or 3 chevrons appear in the dash display, and adjusting the thumbwheel down or up should change the number of chevrons on display - then I would now suspect the Control Module. If pressing "Resume" has no impact, then I would again suspect the Control Module to be at fault, i.e. not accepting commands in both instances.

I will try this next time I get a chance to go out on a decent road. Probably over the weekend.

In regards to the ACC in the RRS, then is is "highly likely" that the parts from a RRS are adaptable to the XK and as there are significantly more (high end) RRS fitted with ACC (it was a standard fit as opposed to an option), then sourcing parts from a breaker of these cars may get you on the road to success, but you will have to remove the nosecone of the XK in order to access the sensor - as you have already found out.

Sorry there is no definitive answer to your problem, but hopefully you are now closer to a solution that is acceptable.

Jim Mann

Thanks for the info Jim. I will persevere !

[JimMann]

Hi Steve, the warning light (2) I referred to is the same warning light you are referring to.

In normal (ACC) operation on a clear road, this light is NOT illuminated, but it comes on when the car senses there is an obstruction it needs to take note of ahead i.e., it has engaged "Follow Mode" - it sees the car / vehicle ahead and is now adjusting your speed down to that of the vehicle ahead.

Forward Alert (16) serves quite a different purpose and is used either in conjunction (automatically) with ACC or independently of ACC with the ACC switched off. Forward Alert can be engaged by the driver, independent of ACC use, using the switch in the knee bolster pack - where the fuel flap release is situated. Refer to Forward Alert in the handbook for more information.

With the clarification of amber light 2, this means that the sensor is "seeing" an obstacle ahead and is in Follow Mode, but it has not yet put the car closing indicator up in the centre message display (car + chevrons). Note the light 2 is not illuminated permanently to warn the driver ACC is "ON", it only illuminates when the ACC is in "Follow Mode" and actively following (maintaining a gap to) the vehicle ahead.

It may be that a build up of crud in and around the radar sensor in the nosecone is providing the car with a permanent sense of there being an object / vehicle ahead. Or, more likely, the sensor has a fault.

If the car is in Follow Mode, then it has to also think that the ACC is "ON". If that is actually the case, then there should be a "Set Speed" display, along with a number, (speed in MPH) at the second line of the dashboard central display screen (top line indicates gear selection). Is there any such display on your car? Look at the "General Information" section of your handbook - probably around page 86. If there is no "Set Speed" display, then the ACC is not actually switched on and therefore the Follow Mode light is activated without cruise control engaged, once more pointing to a likely sensor fault.

Jim Mann

[dyrham663]

Thanks again Jim.

I have obtained a second hand RR sensor from Ebay already in anticipation!

I will ask the Autoclassico garage how much to take the bumper off, replace sensor and see it that cures it. No obligation on them. However, if that turns out be a lot I might go back to just living with the problem.

I can either have a constantly flashing light, or take the fuse out and go back to Cruise Unavailable fault message.

Steve

[dyrham663]

After a couple of hours at the garage I can say it is just about possible to change the radar sensor without taking the whole bumper off. You have to remove the bottom engine bay cover which is joined to the bumper by about 20 screws. These were very reluctant to come out and one had to be drilled. Realistically, you need a ramp , then if you are a skilled mechanic, very flexible and comfortable with working above your head mostly by feel then you can swap the sensor. Luckily, I hired such a person!

Still, with fiddling an fettling it was still best part of 90 minutes before being able to to start the car again. Unfortunately, the fault was exactly as before. The 'follow mode' light was blinking. So that either means I fitted another non working sensor or it is something else.

The other possibilities being it is a wiring/connection fault somewhere or it is the control module as the only other part in the ACC system.

Diagnosis says 'control module not communicating'. I didnt get an exact code ... I was losing the will by then.

So, I have obtained the Range Rover Sport control module (second hand from tinterweb £65) from the same era and will look to change that sometime in the future. Not sure if this is a job I can access myself or if another trip to the garage is necessary. They charged £100 for a mechanic , facilities and doing diagnosis on the car over a two hour period which I thought was pretty reasonable these days.

Steve

[andypryce]

Full marks for persistence anyway!

[mike020150]

Hi Steve,

It's worth noting that the speed sensor has a vertical adjustment which has to be within +/- 0.5 degrees for the sensor to work correctly. Working with the nose in place may make that difficult to check and adjust. The control module is much more accessible. It's fitted behind the RH trim panel below the A pillar and should be easy to change. Good luck. Mike.

[dyrham663]

Found this in the manual;

ADAPTIVE SPEED CONTROL RADAR SENSOR
The adaptive speed control radar sensor is mounted centrally behind the front bumper. The
sensor is connected to the Adaptive Speed Control, module via a private CAN bus. If the unit
is replaced in service the unit must be re-aligned vertically.
Horizontal alignment is achieved by putting the sensor in service mode via IDS. The vehicle
is then driven for a short period while the sensor calibrates itself. Calibration is complete
when the 'follow' icon in the instrument cluster stops flashing.

Anyone care to have a go at interpreting that!

Steve

[mike020150]

Try: the vertical adjustment is completed physically (a nut and bolt job) but horizontal alignment is achieved by using Jaguar's IDS system to place the unit in self-learning mode. Mike.

[dyrham663]

Yes, found a bit in the manual about adjusting the vertical angle. That could only be done with the nose fully off so I may have stuffed that anyway. It also talks about driving for two minutes at 55mph for it to recalibrate. You would need to find a three mile stretch of free dual carriageway at least. The more I find out, the less likely I think this can be solved!

Steve

[dyrham663]

Took it for a run around the Bristol ring road and back. No effect on the 'follow mode' light. It was a long shot!

Funny thing now is I used the phone scanner app to look at the DTC's and there are none. Not about the sensor, the controller or anything else on the car. (previous fault codes up the thread were when fuse 15 was removed)

All there is , is the follow mode light flashing. The only error code on the dash is if I press resume or cancel on the steering wheel. It says 'Cruise not available' on the dash for a few seconds then clears.

Going away for the weekend now (in the F pace!) so you will all have to wait for the next thrilling instalment!

Steve