Jaguar XJS Brakes and ABS Problems
On 1989–1995 Teves III cars, start by listening for the ABS pump at key-on: one that won't run is usually its relay, one that won't stop is a blocked feed or the pressure switch, and a red BRAKE light on its own is often the Combined Pressure Switch. On 1995–96 Teves IV cars, C1095 is usually the pump motor's plug, not the module. Dragging brakes or a sinking pedal point to old hoses, calipers and the master cylinder.
How bad is it · Garage, carefully
Amber light alone: drive gently to a garage; red light or sinking pedal: don't drive
With only the amber ANTI-LOCK light the brakes still work, just without ABS. A red BRAKE light on a Teves III car, or a pedal that sinks, means the assist or a brake circuit is failing.
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.
Teves III pump not running — relay, fuses or the pump itself
On 1989–1995 cars the Teves III pump and its sphere supply all the brake assist; there is no vacuum servo. If the pump doesn't run, the assist goes and both the amber ANTI-LOCK and red BRAKE lights stay lit. The yellow pump relay under the dash is the usual suspect, because water gets in and rusts its contacts.
Both lights on from key-on, no whirr from the pump under the bonnet, and a very hard pedal or one that sinks and comes back slowly.
Switch on and listen: the pump should run, the amber light should go out first, then the red, and the pump should stop. If it stays silent, look for 12 V on both sides of the two ABS fuses in the under-dash panels, then at the pump plug with the key on, then pull the relay and look at its contacts.
Clean and lightly sand the relay contacts or fit a new relay, then bleed the brakes, fronts first. If the pump neither turns nor draws current with 12 V and earth wired straight to it, the pump is finished; a used one with its pressure switch and bracket is the usual answer. A plug knocked loose in the boot can bring the lights on too, so after reseating it make sure they stay out.
Combined Pressure Switch on the sphere
The Combined Pressure Switch on the Teves III sphere holds several switches: one starts and stops the pump, the others feed the warning lights. One internal switch that no longer closes under pressure keeps the red BRAKE light lit, and contacts welded shut keep the pump running.
A red BRAKE light that takes longer and longer to go out after starting and then stays on, while the amber light and the ABS itself behave normally. Or a pump that never switches off.
Check the fluid level and the reservoir float switch first. Then bleed the pressure off and test each switch's pins for continuity, once depressurised and once with the pump running. Measure the switch contacts at the plug with the system pressurised and again with the pressure bled off: a contact that reads the same both ways is a dead switch.
Replace the switch after bleeding the system down; it needs a 40 mm spanner. The later type is JLM1908. The early JLM1465 worked with a reversing relay and won't swap in without wiring changes; a 1992 car with the blue-top switch needs no reversing relay.
Teves IV code C1095 — the pump motor plug
From 1995.25 the XJS has Teves IV with an ordinary vacuum servo and no sphere. C1095 reports the pump motor circuit, but on these cars the fault is often the motor's connector or a pump that has stuck, not the module.
ANTI-LOCK light with C1095, sometimes coming on at 10–15 mph; the brakes themselves feel normal.
Clear the code. Unplug the pump motor and feed it 12 V directly, on the brown/blue wire; it should spin.
Clean both halves of the motor connector with contact cleaner, plug it back in and clear the code. Do this before buying parts: good modules, and even a new pump and module, can leave C1095 in place. Teves IV has no relays on its two unswitched feeds; the switched one comes through the main load relay under the dash, and all three go through fuses in the two under-dash panels.
Teves IV ABS controller — cracked solder at its plug
On 1995–96 cars the ABS controller sits under the pump on the passenger side of the engine bay, not in the boot. Its weak spot is dry solder joints where the plug meets the board.
ANTI-LOCK light on with a stored code, ABS out of action, ordinary braking still there.
Rule out the pump motor plug first. Confirm the part number in a parts catalogue before buying: the module in the boot of a 1996 car is cruise control, not ABS.
Fit a replacement controller, LNA2210 (DAC10056 is also quoted); it comes off with Torx screws and the brake pipes stay connected. The cheaper route is to cut the casing open and resolder the plug joints.
A blown diode beside the ABS ECU — amber light stays on
On Teves cars a small diode in the loom beside the ABS ECU and the diagnostic socket sits in the feed to the ABS main relay. When it fails open, the main relay gets no feed and the amber light loses its path to earth, so the light stays on.
Amber ANTI-LOCK light on all the time, and the large YB wire at the ABS main relay dead with the key on and with the engine running.
Check the ECU earths first, terminals 1, 3, 8, 20 and 27, with the ignition off. Then slit the heat-shrink, read the marking and take the diode out: on a multimeter's diode range a good one reads about 0.5–0.65 V one way and OL the other, and a dead one reads nothing either way.
Fit a standard 1N4006 rectifier diode (any 1N400x will do) and solder it in with the band, which marks the cathode, the right way round. The part costs pennies; the dealer version costs many times more.
Pump runs but builds no pressure — blocked or air-locked feed
The Teves III pump draws fluid from the reservoir. Gunk or air in the line between the sphere and the reservoir starves it, so it runs and runs without building pressure.
Pump running non-stop with the key on, nothing at the rear bleeders and nothing from the high-pressure pipe at the pump, often right after rear brake work.
Fill the reservoir to about 1/8 in below the filler and run the pump for no more than 60 seconds at a time.
Disconnect the sphere-to-reservoir line and blow it through, then pressurise the reservoir slightly to prime the pump. The manual's fluid intake hose bleed procedure (70.25.02) primes a pump that has lost its prime. Air in the sphere can push back and unprime the pump again, so keep the pump lower than the rest of the system. After a rebuild, air left in the circuit can bring on both lights under hard braking with a sinking pedal: bleed through at least 2 litres of fresh fluid with the reservoir kept full to the neck.
Old rubber hoses and fluid holding the brakes on
The original flexible hoses swell inside and start acting as one-way valves: pressure gets through to the caliper but bleeds back slowly. Old fluid adds sludge that sticks pistons and valves.
Brakes dragging so hard the wheels won't turn on jacks, pads clamping for up to a minute after you lift off, or no flow at one bleeder. One rear wheel hanging on points to its hose; both rears point to the pressure-reducing valve. All four wheels held on at once points to no free play at the pedal push-rod, holding the brake valve slightly open.
With the brakes locked on, crack the bleeder at each corner. If the wheel frees, the restriction is upstream; slacken the unions one by one working back from the brake until the pressure lets go. Make sure the handbrake is fully off before anything else. On a car that has stood for years, bleed with the rear pads out so the pistons can be squeezed back — a lot of gunk comes out of the calipers.
Replace all the rubber hoses as a set, because one new and one old hose makes the car pull. Flush the fluid, push the pistons back and bleed several times; expect gunk to keep coming for a while. Renew the hoses roughly every ten years. If dragging rears survive new hoses and fluid on a 1989–95 car, the rear pressure delay valve CBC4233 is next. It is no longer made new, so a used one is the usual source; BMW valve 34-33-1-152-494 replaces it once the pipe fitting is changed.
Master cylinder seals — pedal sinks to the floor
After 25–30 years the master cylinder seals let fluid slip past. A pedal that sinks steadily means the front circuit isn't holding pressure: a leak, a hose, the valve block or the master cylinder, but not the pump.
Brakes fine for a few presses, then the pedal goes down; dark fluid. A quiet sink points to the master cylinder; a pedal that buzzes and bounces points to the pump side.
A rectangular reservoir means Teves III, a triangular one Teves IV. On Teves III, pull the ABS fuses: with the front circuit bled and dry the car should brake like a conventional system with a hard pedal. If it doesn't, suspect the master cylinder or the valve block. A long soft first press on a 1996 Teves IV car is usually air: bleed it at the screws like any conventional car and don't push fluid backwards; only the earlier pump-and-sphere systems need the pump running to bleed the rears.
Replace the master cylinder, bench-bleed it before fitting, then bleed the whole system. Cars from 1995.25 use a different master cylinder from earlier ones, and rebuild kits are scarce.
A seized or blocked caliper
A seized caliper makes the car pull and can push enough pressure to the other wheels to lock one. A remanufactured caliper can be blocked inside straight out of the box.
Pull to one side under braking; one caliper that won't bleed although fluid runs freely from its hose; a rear wheel locking after a hard stop. No fluid at one front caliper after work on the brakes can simply be a dry section of the reservoir: it has several, and the one feeding that side may have run empty.
Check flow from the hard pipe and from the hose before blaming the caliper. Swap bleeder screws side to side to rule out a blocked screw or a shipping plug. Keep every section of the reservoir topped up to the neck while bleeding; a vacuum bleeder helps. An ANTI-LOCK light that stays on after brake work is often just an incomplete bleed.
Replace or rebuild the caliper. Some cars have single-piston rear calipers (JLM12422 / JLM12423) while kits are often listed as twin-piston, so check the number. On a car that has stood for years, do pads, hoses and several fluid changes before suspecting the ABS.
Teves III sphere has lost its gas charge
On Teves III the nitrogen sphere stores the pressure that powers the brakes, and it loses its charge after about 10–12 years. A tired sphere makes the pump run after nearly every press, brings on the amber light and in the end takes the assist away.
Pump running after almost every stop instead of every half-dozen presses; amber ANTI-LOCK light; assist that comes and goes, then disappears. A tired sphere alone won't hold the amber light on steadily — the ABS pressure switch trips at a lower pressure than the red-light switch, so it shows as a busy pump and an occasional red light under hard braking. A steady amber light points to a wheel sensor or the switch.
Count how often the pump runs. Before touching the sphere, bleed the pressure off: ignition off, press the pedal up to 20 times until it's rock hard, and still expect a spray of fluid.
Worth trying first on a sphere that has never been changed: fit a new one. JLM1907 is the Jaguar part; a GM 25676065 sphere is far cheaper but needs adaptors. A used sphere isn't worth fitting.
Teves IV front wheel speed sensor
The front sensors sit behind the hubs and collect greasy debris. The front passenger sensor is the usual one to fail, and a sensor whose mounting tab has broken can be held in place only by dirt.
ANTI-LOCK light that comes on after a short drive, clears and comes back.
Have the code read rather than just cleared. A resistance of about 1.1 kΩ doesn't prove a sensor good: spin the wheel and read AC volts. Reaching a front sensor means releasing the upper ball joint.
Cleaning buys time, but the gaps between faults get shorter. A new sensor, DAC4841 left or DAC4842 right, cures it; they are not interchangeable. A loose sensor can be bonded back in place for now.
Teves III valve block — sludge or worn seals
Old fluid leaves sludge in the valve block and its filters. A valve that doesn't return fully holds pressure on, and worn block seals let fluid escape instead of reaching the brakes.
Brakes that grab and then let go, a caliper staying on after release, or fluid and crud on the electrical side of the valve block.
Pressure-bleed the front circuit: open the caliper bleeder, put 12 V on the main valve at the front of the master cylinder (two-pin plug) and touch the pedal. Then energise the front solenoids one at a time using the valve block diagram.
Worth trying before new parts: flush repeatedly with fresh fluid, which can take months to free a sticking valve. Seals for the block are hard to find, so a leaking block usually means a good used one.
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.
Work out which system you have
A rectangular reservoir means Teves III (about 1989 to 1995.25: pump and sphere, no servo). A triangular one means Teves IV (1995.25 on: vacuum servo, no sphere). Cars without ABS have a conventional servo.
freeRead which light is on, then the codes
Amber ANTI-LOCK alone: ABS is off but the brakes work. Red BRAKE: pump pressure or fluid level. Teves III gives flash codes through the diagnostic connector; a parts-store scanner only talks to 1996 OBD-II cars.
freeKey on and listen to the pump
On Teves III the pump should run, the amber light should go out, then the red, then the pump stops. Silent: fuses, relay, pump plug. Never stopping: the feed line, priming or the pressure switch.
freeCheck the fluid
Keep every section of the reservoir topped up to the neck, especially while bleeding. Dark fluid has absorbed water; flush it.
freeTeves IV with C1095: power the pump directly
Feed the pump motor 12 V, clean its plug and clear the code before buying a module or a pump.
freeDragging or pulling: bleeders and hoses
Crack each bleeder with the brakes stuck on. If that frees the wheel, renew the rubber hoses as a set and flush the fluid.
a set of hosesBleed the Teves way
Bleeding takes far longer than on a conventional car. Follow the manual's procedure, power-bleed the rears with the pump, and run the pump no more than 60 seconds at a time. Discharge the sphere before you start and crack each bleeder only slightly, ideally with a vacuum bleeder or a one-way valve.
fluid and timeOnly then buy the big parts
Sphere, pressure switch, master cylinder or ABS controller, in the order the symptoms point. Bleed the pressure off before opening any Teves III part.
sphere, switch, master cylinder or controllerThe fuses named above — where they sit
The highlighted position is the one the procedure talks about. Pulling a fuse is a stop-gap, never a repair: check what the circuit feeds before you pull it.
Circuit descriptions from the Jaguar fuse tables, 1994 edition. Drawing by jagaux.com from the factory electrical guide. Fuse layouts change between model years — read the legend on the lid of your own box before pulling anything.
What it usually isn't
Don't spend money here first:
If none of this finds it:
On jagaux.com
- Jaguar XJS Instrument Cluster, Gauges Not WorkingIf other warning lamps act up along with the ABS lights.
- Jaguar XJS Electrical Problems, Bad EarthsIf the lights came on after electrical work or with other faults.
- XJS fuse boxesTo find the ABS fuses in the under-dash panels.
- Jaguar VIN decoderConfirm your exact model year, engine and factory options before ordering parts — free.
Ratings, fuse numbers and torque figures vary by model year and market. Read the legend on your own car before pulling anything, and use the figures in the manual for your car, not the ones in a video.
Check your VIN: exactly which car you have and which bulletins apply to it.