Hello - I had the AFS Warning light come on last week on my 2008 4.2 XKR intermittently for a few days, but now permanent. Having diligently read through the excellent posts on here I think I have come to the conclusion I will need to buy a new headlamp, but before then thought I will just check if there is anything else I could try.

I didn't have a scanner available initially, so took a punt on replacing the Headlamp ECU in the drivers footwell - no change the warning light was still on, could get it to go off briefly by turning the ignition on/off twice, but then came back on again. So I decided to buy a scanner Carsoft LR v3.0 to get the codes, and also ordered a new (second hand) AFS Power module. The scanner showed U1A39 "communication malfunction of right actuator". So I removed the right headlamp and replaced the power module. No change same error. Next step in trouble shooting, I removed the LH headlamp and switched them over, so Left in the right socket, right in the Left Socket. New Code U1A38 "communication malfunction of left Actuator".Next I switched power modules over the two headlights - same code U1A38. So the error moves with the headlight assembly not the power module.

Next I tried checking for continuity from the headlamp socket to the AFS Power module on the headlights, on the Power module socket there are 4 connections, one in each corner, and 20 pins in the middle. I got continuity from pin 5 (Power), Pins 6&7 (Ground) but nothing from Pin 4 (Signal?) showing on the AFS Power module Plug. It is the same on both headlamp units, so I am not sure how the AFS module communicates to the ECU, and whether I should be able to get continuity on that connection, or its in one of the Pins, which my probe is too big to get in to. But I can see power and ground arriving at the AFS Power module socket from the main socket into the headlamp.

Finally I thought there must be something wrong in the RH Headlamp so I took the lens off and removed the reflector, but couldn't get to the plug for the AFS power module (and not sure what I am checking for) so decided to put it all back together. All the wires look and feel good - I saw some people had issues with frayed insulation - I can't see any of that.

I have it booked in with an auto electrician, but other than replacing the headlamp (which is very expensive) not sure what else I can do, so thought I would post this to see if anyone has any advice on anything else I could try.

The only other thought I have had is to see if I can get the AFS coded out, disable the AFS power modules and live without AFS completely.

All the lights are working, though the left hand one has now drooped (RH Lamp is pointing straight), I am assuming I can manually adjust that and disable the AFS power module so that I can use the car in the meantime.

Any Ideas that I could try, or is it time to get a new headlamp?

 

You can edit the vehicle's CCF in SDD to remove fitted with AFS. The only trouble spots for AFS that I've run into are the wiring inside the lamp assembly (but you say yours is fine), the AFS modules on the headlamps or the control module in the footwell. Of course a full vehicle soft reset by disconnecting the battery and also verifying the battery's fully charged wouldn't hurt if not done already.

 

Me, I give the headlamp assembly a solid bonk with the side of my hand and all is well for quite a long time.

 

Thanks - the wiring that I can get to looks and feels OK (couldn't get to the wiring on the plug for the AFS Power module), I did disconnect and reconnect the battery - didn't seem to make any difference, I will put it on charge and try again, during testing I did at one point see a low battery warning and the battery is about 5/6 years old, so maybe related.

 

I have tried that as well - didn't work for me though

 

Check the height sensors on the suspension. They wear out, or can be knocked out of position if someone is working on the suspension. A decent JLR compatible code reader will post the voltage on the sensors.

 

I’ve had AFS errors when the battery dipped below 12.6 volts. Make certain the battery’s 12.6volts resting overnight and can handle a load without dropping below 11 volts.

 

I will take another look over the weekend, but pretty sure I was seeing sensor angles for both front and rear in the icarsoft scanner, and the code I am getting is saying it can't see the power module in the faulty headlamp, whichever side I plug it into, and whichever power module I use.

 

No change with the old battery fully charged, but I will replace the battery this weekend as its old anyway and see if that makes any difference (fingers crossed, but not much confidence that will fix it). For now I have manually adjusted the headlamps to point forward, and a bit of black tape on the dash blanks out the flashing warning light (out of mind out of sight).

I am coming to the conclusion that I will need a very expensive new headlamp unit, before buying one just want be sure I have tried every other possibility, as I would hate to pay all that money and still have the problem. In my mind since the fault code follows the headlamp the car wiring itself must be fine, the central headlamp ECU also knows where the faulty headlamp is - so that seems OK, only really leaves the headlamp itself. I don't think there is anything in the headlamp other than wiring/motors, so maybe a faulty connector or faulty wiring but I wasn't able to find a wiring fault. With the code I am getting I think either the power module isn't getting power/ground, or it can't communicate on the canbus which is why the ECU can't see it in that headlamp. I can trace the power and ground and they have continuity to the power module socket in both the working and faulty headlamp. I can't trace the canbus for the power module in either headlamp using continuity on a multimeter, not sure if that is the right way to test for the canbus or not though as I haven't really had any experience with a canbus.

 

https://www.jaguarforums.com/forum/newreply.php?do=newreply&noquote=1&p=2829844
For anyone with a similar problem in the future... I took the car to a local car electrician, he did the same checks as me, but dismantled the headlamp further, he was able to confirm this module inside the headlamp was causing the issue. On google that part number comes up as a fitting a BMW 7 Series, but I can't see one for sale only sold ones, so since the car has barely put a foot wrong in the last 14 years I have owned it I have decided to get a brand new headlamp for it, which I plan to collect and fit tomorrow. Will then sell my headlamp on eBay as someone else may want to repair it, or use it without the adaptive function.

Thanks for the advice everyone gave.

 

FINAL UPDATE: I bought a brand-new headlamp -(very expensive) and the fault was exactly the same, I was not very happy at this point. Assuming the new headlamp wasn't faulty the electrician then repeated all the diagnostics steps I had taken from scratch, when he switched headlights from left to right and vice versa he got exactly the same result, ie the code 39(right fault) changed to a code 38(left fault) (following the headlamp). However when he unplugged the left hand headlight he said it reverted to code 39(right fault). His explanation was that somehow the car remembered which headlight was which so moving the right one across the code followed it incorrectly. I am not sure how that could happen but he did find a problem with the wiring to the right hand headlamp which had been rubbing near the airbox, he fixed the wiring and everything is working now.

Just in case anyone else ever gets a similar problem and the fault moves with the headlamp, double check all the wiring before assuming it's the headlamp, and you could save the cost of a headlamp replacement.

My original headlamp is now going be put back together and sold on eBay as there isn't anything wrong with it, so may recover some of the cost and help someone else out who really does have a faulty headlamp