Jaguar XJ6 (X300) Key Fob Not Working, Fob Programming
On the X300 a dead fob is usually the fob itself: worn rubber buttons, dirty switch contacts or weak cells. Next comes programming: the car forgets its fobs, refuses to learn while it thinks a door is open, or never learns a fob on the wrong frequency. I'd start with fresh cells and the buttons, then re-teach every fob in one session.
How bad is it · Safe to drive
Safe to drive, since the key still opens and starts the car
The fob only works the locks and the alarm. Keep the black master key with you: the green valet key won't open the boot.
Which one applies to yours depends on your symptoms, your model year and what has already been done to it.
Likely causes, most common first
Read the check cost before the odds: a free check that rules a cause out beats a likely guess that costs money.
Worn rubber buttons or dirty switch contacts in the fob
Each button presses a tiny switch on the board through a rubber pad. The pads wear through or sit too deep, and the carbon they shed fouls the switches.
It needs several presses, works after a tap on the palm, or its lamps flash on their own; fresh batteries help only for a while.
Look at the rubber buttons first: worn through, or pushed in against the board? Then open the fob and look for a switch lifted off the board on one side.
New rubber buttons, part JLM20626, flick out and squeeze in from outside in a couple of minutes. Clean the board with alcohol; resolder a lifted switch, or fit new KSR251G LFS switches.
Flat, weak or badly seated fob batteries
The fob takes two stacked CR2016 lithium cells. Its lamps can still glow on cells too weak for the car to hear, which looks exactly like a fob that has lost its programming.
Dead straight after a battery change, a lamp that stays lit until the cells come out, or lamps working and the car ignoring them.
Test each new cell with a meter, since a brand-new one can be dead. Plus side up, a matched pair, and the cover pressing them firmly; bend the contact tab down if it doesn't.
A good matched pair of lithium cells. After fitting them, leave the buttons alone for two minutes.
The fobs have dropped out of the security module's memory
The security and locking module in the boot stores the fobs it was taught. Teach every fob you keep in one session, because teaching one can wipe the others.
Both fobs stop at once with good batteries; their lamps flash but nothing happens.
Boot lid and driver's door open, ignition to II. Rock the valet switch in the centre console storage five times: one chirp and a headlamp flash mean it's listening. Press the large lock button on the first fob, rock the valet switch once, press the next fob for two chirps, and so on. Run five cycles in all, repeating the last fob if you have fewer. After 15 seconds two chirps close the session; ignition off.
Re-teaching brings the fobs back, even on their old batteries. The first fob takes driver memory 1, the second memory 2.
The car thinks a door or the boot is open, so it won't learn or lock
The module refuses learning mode, and refuses to lock, while it reads anything as open. A dead valet switch or an unplugged alarm sounder can also keep it from learning.
No chirp after five rocks of the valet switch; or unlock works but lock gives a different beep instead.
Open and shut every door and the boot firmly, not only the driver's door, then start again. Look for a door or boot-ajar lamp. Check the valet switch for continuity and that the sounder is plugged in.
Cycling all the doors can put it straight into learning mode. A faulty boot-latch microswitch is a dealer part and easy to change; unplugging it restores the locking meanwhile, at the cost of the boot lamp and warning.
A fob on the wrong frequency for the car
The X300 used two systems: 315 MHz, fob DBC11510, on 1995 and early 1996 cars, and 433.92 MHz, fob DBC11512, after. Fob and module must match, and the egg-shaped fobs look the same apart from the label.
A new or used fob lights up, but the car never learns it, or learns it and then ignores it.
Read the frequency on the back of the fob and on the security module; on the X300 it sits on top of the left wheel arch in the boot, forward of the fuel filler. In North America long-wheelbase cars from VIN 758729 and short-wheelbase from VIN 759614 are 433 MHz.
Buy by frequency, not by looks. A 315 MHz car can learn a Saab 900/9000 remote, part 4550075, like a Jaguar fob. A later car can take a 1995 module and then cheaper fobs; an X308 module won't interchange.
The loom into the boot lid broken at the right-hand hinge
The loom flexes at the right-hand hinge every time the boot opens. Broken wires there cut the boot release, the boot-closed signal and the dash lock switch feed.
Boot button dead, or the lock motor whirs and the lid stays shut; or the remote won't learn because the car can't see the boot open.
Open the loom sleeve at the right-hand hinge and test each wire while flexing it.
Repair the broken wires, and leave off the cable tie that bends them sharply.
Valet mode has locked the boot
With valet mode set, the boot ignores the remote, the dash button and the boot button. The green key is the valet key and never opens the boot lock.
Doors work normally, but the boot won't open, with a warning tone from the dash or boot button.
Check the valet switch in the centre console storage. Try the black master key in the boot lock.
Worth trying: cancel valet mode. Shut out with no master key, the boot rod can be reached through the hole behind the number plate.
A poor connection at the aerial in the rear screen
The fob receiver's aerial is printed into the rear screen at the top centre, marked High Security Antenna. A loose or corroded screw connection, or a replacement screen without the aerial, cuts the range to almost nothing.
It works only held to the rear glass or the door handle, or only in cold weather, or fails in one particular car park.
Find the connection inside at the top centre of the rear screen; clean it and retighten gently. Has the rear screen ever been replaced?
Worth trying: clean and retighten, not too hard, or the element lifts off the glass. Strong radio traffic near 433 MHz can swamp the fob in some places; move the car before blaming it.
Fob, key and console switch all dead: the lock relays or the security module
When nothing locks electrically, the lock relays and the security module itself come next. An old relay can click without its contacts carrying current.
No electric locking from fob, door key or console switch; the manual locks still work.
Prove the fob first on an RF tester. Then the lock relays, then the module on the left of the boot.
Worth trying: renew the lock relays. A used module must carry the same suffix (LNA2600BB001 is 315 MHz, LNA2600CC001 433 MHz), and changing frequency means new fobs.
The order to check them in
The point of the order is money: each step either rules a cause out or makes the next one worth doing. Green is free, amber costs a little, red is the one to arrive at last.
Two fresh matched CR2016 cells, then the rubber buttons
Test the new cells; a worn button pad is a two-minute swap.
cheapRe-teach every fob in one session
Boot and driver's door open, ignition II, valet switch five times.
freeNo chirp? Shut every door and the boot, check the valet switch
Watch for a door or boot-ajar lamp.
freeA new fob won't learn? Match its frequency to the module
315 MHz on early cars, 433 MHz later.
freeShort range? The aerial connection on the rear screen
Clean and retighten gently.
freeBoot won't open? Valet mode, then the hinge loom
Try the black master key first.
freeNothing locks at all: the lock relays, then the security module
Same suffix and frequency on a used module.
relays; a used moduleWhat it usually isn't
Don't spend money here first:
On jagaux.com
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- Jaguar radio code generatorFree. For when the radio asks for its code after the battery has been off.
- Jaguar XJ6 (X300) Trunk Won't Open, Boot ReleaseIf the boot itself won't open from any button or the key.
- Jaguar XJ6 (X300) Alarm Keeps Going OffIf the alarm keeps going off even when the fob works.
- Jaguar VIN decoderConfirm your exact model year, engine and factory options before ordering parts — free.
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Check your VIN: exactly which car you have and which bulletins apply to it.