Jaguar XJ6 / Sovereign
XJ40 · 1986-1994Faults written up for this generation: likely causes and the order to check them in.
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12
Jaguar XJ40 Brake Problems, ABS and Brake Accumulator
On the XJ40 the usual cause of ABS and BRAKE lights, a pump that runs on every press and a pedal that goes hard is an accumulator sphere that has lost its gas charge…
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14
Jaguar XJ40 Air Conditioning Problems
On the XJ40 warm air is usually a slow leak, and the oil goes out with the gas. I'd read the sight glass and look at the back of the compressor first, then the condenser…
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7
Jaguar XJ40 Alternator Not Charging, Battery Light
On the XJ40 the alternator is rarely the whole story. The small feed that wakes it runs through the centre console fuse box, and a loose plug there stops the charge.
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9
Jaguar XJ40 Battery Drain, Flat After a Few Days
On the XJ40 the battery is rarely at fault — something in the car stays awake, most often the door lock heaters on early cars, then a hidden lamp or a window circuit…
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3
Jaguar XJ40 Belt Squeal, Crank Pulley Wobble
On the XJ40 a loud screech for the first 10-15 seconds after a cold start is very often the harmonic balancer, the rubber-bonded crank pulley, slipping on its hub, not…
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13
Jaguar XJ40 Blower Motor Not Working
The XJ40 has two blowers, and the usual reason one stops is a cracked solder joint in its footwell fuse box, then the speed-control transistor (high only) and worn…
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8
Jaguar XJ40 Bulb Failure Warning
The bulb-failure warning on these cars is usually honest: a bulb that still lights but has gone high-resistance, a loose number-plate bulb, a corroded wing repeater…
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5
Jaguar XJ40 CD Changer E-01, E-02 or NOT CONT
The boot changer on these cars is a rebadged Alpine, and its codes are specific: E-01 a disc-change failure, E-02 a disc left in the player.
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10
Jaguar XJ40 Central Locking Not Working
On the XJ40 dead central locking is most often the locks falling out of step, or one sticky door that can't finish its stroke, so the system gives up with a click.
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8
Jaguar XJ40 Check Engine Light, Fault Codes
On these cars the check engine light always comes with a code stored in the engine computer, and the VCM in the dash shows it.
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11
Jaguar XJ40 Cranks But Won't Start
On the XJ40 it's usually a cheap part: a distributor rotor whose built-in resistor has failed while it still looks new, the crank sensor, a relay in the fuel pump chain…
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9
Jaguar XJ40 Dashboard Warning Lights
On the XJ40 the dashboard trouble is usually the dimmer module, cracked solder joints in the cluster, or a warning that's real but misread — a pad sensor lead…
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3
Jaguar XJ40 Door Handle Repair, Door Won't Open
On the XJ40 a door that won't open is usually the rod between the outside handle and the latch set too short or too long, and a handle that has been fighting a badly set…
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6
Jaguar XJ40 Front Suspension Knock, Worn Bushes
On the XJ40 a front knock is nearly always rubber: the damper top and bottom bushes and the anti-roll bar bushes go first, then the wishbone and subframe bushes…
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8
Jaguar XJ40 Fuel Pump Problems
On the XJ40 a silent fuel pump is more often its relays or wiring than the pump itself: the pump relay is switched through the oxygen sensor heater relay, and either can…
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7
Jaguar XJ40 FUSE 1 or FUSE 2 FAIL Warning
FUSE 1, FUSE 2 or FUSE 3 names the fuse box, not a fuse: 1 is the right-hand door pillar box, 2 the left-hand, 3 the centre armrest.
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6
Jaguar XJ40 Head Gasket Failure, Low Compression
On the XJ40 a suspected head gasket is one of two things: the gasket letting coolant into a cylinder, or a burnt exhaust valve on one cylinder.
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3
Jaguar XJ40 Headlights Not Working
A dead or dim headlamp on these cars is usually a corroded or chafed wire in the front loom, or an oxidised fuse feeding that one beam.
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6
Jaguar XJ40 Heater Not Working
On the XJ40 no heat is usually the heater valve stuck shut, a thermostat stuck open, or low coolant.
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5
Jaguar XJ40 Immobiliser Problems, Won't Start
The XJ40 has no key transponder; what stops it starting is the security system's start disable or an add-on alarm with its own immobiliser.
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5
Jaguar XJ40 Low Oil Pressure
On the XJ40 a gauge that drops to zero at hot idle is almost always the sender or its connector, not the engine.
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6
Jaguar XJ40 Misfire
On the XJ40 a misfire is nearly always on the high-tension side: leads arcing in the damp, a rotor or cap breaking down, a coil failing as it heats, or the distributor…
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9
Jaguar XJ40 Oil Leak
On the XJ40 most oil leaks start at the top and run down: the cam cover gasket at the rear right corner, or the cooler pipe O-rings under the oil filter.
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11
Jaguar XJ40 Overheating, Radiator and Cooling Fans
On the XJ40, running hot is nearly always airflow or a lost hose: a slipping fan clutch, dirt packed between the radiator and the A/C condenser, hardened shroud flaps…
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5
Jaguar XJ40 Power Aerial Stuck
Usually it's the cheapest part: a mast costs about £15–20 and on most cars goes in from outside in 15–30 minutes, the radio driving the old one out and the new one in.
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7
Jaguar XJ40 Power Steering Problems, Steering Rack
On the XJ40 most power steering trouble is fluid and hoses before it is the rack: check the level and the right fluid for your year first, then hunt leaks under load and…
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4
Jaguar XJ40 Vibration at Speed, Prop Shaft
On the XJ40 a vibration that comes in at one band of speed is usually the prop shaft: the rubber Jurid coupling at the diff, the centre bearing, or the shaft itself out…
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7
Jaguar XJ40 Radio Code, CODE or WAIT on Display
After the battery has been off the radio shows CODE and wants four digits. Look under the bonnet first — on many cars the code is on a paper label there.
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6
Jaguar XJ40 Radio Not Working or Cutting Out
First question: what died with the radio? On 1993–94 cars the heater fan, climate panel and electric seats share relay module H with it, and its solder joints crack…
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9
Jaguar XJ40 Radio Replacement and Stereo Upgrade
Almost any single-DIN radio fits an XJ40 once the sloped factory unit is out, but the plugs changed with the years and nothing plugs straight in on earlier cars.
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9
Jaguar XJ40 Rear Suspension Problems
On the XJ40 most rear suspension trouble comes back to the self-levelling system or to a half-done conversion away from it: short self-levelling springs left in, or the…
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12
Jaguar XJ40 Rough Idle and Stalling
On the XJ40 a rough, hunting or stalling idle is usually dirt and air rather than electronics: a carboned or sticking idle speed control valve, a gummed throttle body…
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2
Jaguar XJ40 Speakers Not Working or Crackling
First pull the volume knob: on this radio it is also the balance, and a side turned fully off looks like a dead speaker.
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2
Jaguar XJ40 Steering Wheel Shake
On the XJ40 a shake in the steering wheel is usually a front tyre or a warped front disc. If it comes at one speed, I'd look at the tyres first.
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13
Jaguar XJ40 Transmission Problems, Limp Mode
On the XJ40 most gearbox trouble is electrical or simple before it is mechanical: the warning light and limp-home on the 4HP24 come from a relay, the throttle sensor…
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4
Jaguar XJ40 Turn Signals Not Working
On these cars there's no flasher relay: the central processor behind the glovebox pulses the indicator relays inside the four corner modules.
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7
Jaguar XJ40 Window Motor, Windows Not Working
On the XJ40 a dead window is most often the door switch pack, not the motor: its built-in relays click but their tarnished contacts can't pass motor current.
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8
Jaguar XJ40 Wipers Not Working, Wiper Motor
On these cars a wiper that won't park, stops mid-screen or won't switch off is almost always the small in-line park fuse, or the microswitch and cam inside the motor…
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6
Jaguar XJ40 Won't Crank, Just Clicks
On the XJ40 a click and no crank is usually the battery, its connections or the gear selector switch — the starter itself comes last.