Fault File
All models / All cars / Saloons & estates / Jaguar XJ

Jaguar XJ

All generations and engines together · 10,331 MOT tests in the 2025 data · typical mileage at age 7: 56k

Reliability verdict
BBy age
CBy miles

Graded against its peers

Better than most saloons and estates for its age, though about average per mile driven. Watch suspension and brakes. A solid used buy, provided its MOT history has no repeating suspension advisories.

First-time failure at age 7
12.9%
Across 774 tests. The average for saloons and estates is 17.4%.
First-time failure at 50-60k miles
15.2%
Across 1,022 tests. The average for saloons and estates is 16.8%.
Rank in its class
6 of 34
1 = lowest failure rate among the 34 saloons and estates we can rank.
Typical mileage at age 7
56k miles
How far the average car has gone by seven years old. Low-mileage models can look better by age than they are.

Generation

Split by first-registration year. Cars registered in a changeover year can belong to either generation.

What owners report

Reported

Owner folklore from forums and the motoring press, with how well each report stands up. Most of it never shows up in an MOT, which is why this section exists at all.

Rear air suspension sagging or failing

Partly in the MOT data

The self-levelling rear air suspension can leak down overnight, leaving the car sitting low on one corner by morning, or the compressor can wear out and struggle to keep pressure. It's most reported on the X350/X358 (2003-09), where air lines, valve blocks and the compressor itself all wear with age; the X351 (2010-19) redesigned the system and is markedly less troubled by it, though owners still report the odd compressor swap. This lines up with the measured MOT data, which shows suspension as the standout fault area for this model, though the actual MOT failure is more often a worn top mount or ball joint than the air system itself, since a bag going soft usually gets fixed (or ignored) long before test day.

Reported from 80k+ miles, worse on X350/X358 · repair £400-1,200 per corner or compressor · sources: kmotors.co.uk common faults guide, Jaguar Forum (X350 air suspension fault thread)

Diesel particulate filter fire risk (2.7 V6 diesel)

Confirmed pattern

On 2005-2008 XJ and S-Type cars with the 2.7 V6 diesel, a run of short journeys could load the DPF with unburnt soot and hydrocarbons faster than the engine management accounted for, occasionally leading to smoke or fire from underneath the car. This was serious enough to trigger an official safety recall for a software recalibration, so any car from this window should have the fix on record. It doesn't affect the later 3.0 diesel in the X351.

Affects 2005-2008 2.7 diesel only · recall was a free software fix · sources: NHTSA recall filing, Jaguar Forum recall thread

V8 timing chain tensioner wear

Emerging

Early 4.2 V8 engines (pre-2007ish, X350) used plastic timing chain tensioners that can crack with age, letting the chain rattle on start-up and, in bad cases, jump enough to bend valves. Jaguar quietly moved to metal tensioners and Morse chains later in the X350's life but never ran a public recall over it. The later 5.0 V8 (AJ133, used in X351) has its own history of timing chain and guide wear, well-known enough to have drawn a US class-action suit, with failures reported anywhere from 80,000 to 150,000 miles; a rattly cold start on any V8 XJ is worth walking away from or budgeting for.

4.2 pre-facelift and 5.0 AJ133 · repair £1,500-3,000+ if guides/chain need replacing · sources: Jaguar Clubs of North America (JCNA), repairpal.com, Jaguar Forums timing chain class action thread

Electrical gremlins and infotainment dropouts

Emerging

X351 owners report the touchscreen infotainment cutting out and rebooting while driving, sometimes alongside revs dropping, warning lights lighting up, or the car briefly losing power, most often traced to a tired battery, a failing alternator, or the start-stop system's contactor rather than the head unit itself. A fresh, correctly-specified AGM battery cures a lot of it, which tells you how sensitive the electrical system is to voltage dips. Jaguar hasn't acknowledged a specific fault; owners largely diagnose it themselves via forums.

Reported across X351 age range · battery/alternator fix £150-600, deeper module faults more · sources: Jaguar Forum (electrical gremlins threads), JagInfo.org

3.0d throttle body clogging and DPF regen failure

EmergingDiesel only

On the X351's 3.0 diesel, carbon build-up in the throttle body can trigger a 'Restricted Performance' message, and if it isn't sorted it can stop the DPF completing a regeneration, eventually leading to a blocked filter and a 'DPF Full' warning. Inlet manifold and rocker cover oil leaks cause the same warning message and get confused with it. A clean or replacement throttle body is usually a few hundred pounds; a blocked DPF replacement runs well into four figures.

3.0d only, any age once mileage is high · throttle body clean/replace ~£200-500, DPF replacement £1,500-2,500 · sources: kmotors.co.uk common faults guide, PistonHeads (XJ diesel DPF thread)

Corrosion around bootlid, door bottoms and wheelarches

Disputed

Some X350/X358 cars bubble around the bootlid seam, lower door edges and wheelarches earlier than you'd expect from an aluminium-bodied premium saloon, usually put down to stone chips and poor drainage rather than a factory-wide defect. Owners are split on how common it really is; some cars go 15+ years untouched while others need panel work by 10 years old. Worth a proper look underneath and around the seams regardless, since a full respray on an alloy body is not cheap.

X350/X358 mainly, from ~10 years old · localised repair £300-800, full panel work more · sources: Honest John (Jaguar XJ 2003-2009 review), classics.honestjohn.co.uk

What to check on this car

Ranked from this model’s own MOT record, then from what owners report.

Saveable checklist

From this model’s MOT record

The physical checks its own defect data says are worth your time, most telling first.

Bushes and ball joints Drive slowly over broken tarmac with the windows down and listen for clonks from either end. Back at the car, have someone rock the steering wheel while you rest a hand on each front wheel; play you can feel through the tyre is a worn joint.Recorded on 7.4% of tests at age 6-9 · class average 5.9%
Brake pipes underneathRuns high on this model Follow the metal brake lines with a torch where they run along the sills and over the rear axle. White crust or flaking metal means they are corroding, and the online MOT history usually shows the same advisory creeping up for years before the fail.Recorded on 1.5% of tests at age 6-9 · class average 0.4%
Coil springs Look through the wheel spokes at the bottom coil of each spring; when springs snap it is usually there, and the break is visible. Step back and check the car sits level too. A dropped corner is often a broken spring.Recorded on 2.1% of tests at age 6-9 · class average 1.4%
Underneath, with a torchRuns high on this model Get down and look at the sills, the subframes and the rear suspension mounting points. Flaking scale and bubbling matter; light surface rust does not. On older cars this is the one check that finds the fault that scraps them.Recorded on 1.3% of tests at age 6-9 · class average 0.6%
WheelsRuns high on this model Look at each rim for kerb damage and check no wheel nuts are missing. A steering wheel that shimmies between 50 and 60 on the test drive often turns out to be a buckled or badly balanced wheel.Recorded on 1.3% of tests at age 6-9 · class average 0.6%
Lights and horn walkround With a helper, run every light: dipped, main beam, indicators, brake lights including the high-level one, reverse, fog, and the horn. On newer cars a dead LED section can mean replacing the whole lamp unit rather than a bulb.Recorded on 1.7% of tests at age 6-9 · class average 1.2%
Leaks Look at the ground where the car usually stands, then glance under the engine after your test drive. Fresh drips of oil or coolant are the cheapest warning you will ever get about a car.Recorded on 1.1% of tests at age 6-9 · class average 2.0%

Worth doing on any used car

These judge the seller’s upkeep rather than the model, and they are where the haggling money is.

Tyres, all four Check the tread across the full width of each tyre, inner edge included, and look for cracking and mismatched brands. A set of decent tyres is £500 or more on most cars, which makes this the easiest money to take off a price. If the pressure warning light is on, budget for sensors too.Recorded on 29.7% of tests at age 6-9 · class average 20.1%
Pads and discs Look through the wheel spokes at the brake disc. A pronounced lip on its outer edge, or a rusty and scored face, means discs and pads are due all round, a few hundred pounds on most cars. A haggling point rather than a reason to walk away.Recorded on 8.1% of tests at age 6-9 · class average 10.1%
Windscreen and wipers Scan the glass in daylight for chips, especially in the driver's line of sight where even a small one can fail the MOT. Run the washers and check the wipers clear without smearing.Recorded on 1.6% of tests at age 6-9 · class average 2.0%

Because of what owners report

Drawn from the reports above rather than the MOT data. These are the model-specific ones.

Leave the car overnight and check its ride height first thing in the morning. Sitting low on one corner or noticeably lower than normal points to a leaking air spring or a tired compressor.
Listen for rattle on a stone-cold start, especially on V8 petrol cars. A metallic rattle that clears after a few seconds can mean a worn timing chain tensioner; don't buy without an inspection.
Check the service history for a DPF-related recall or software update on 2005-2008 2.7 diesel cars. No record of it means the fix may never have been applied.
On a diesel, watch for a 'Restricted Performance' message during a longer test drive under load. It usually means a dirty throttle body or an early DPF problem, not something to shrug off.
Turn on the infotainment screen and leave the engine idling for a few minutes. Any freezing, rebooting or the screen going blank suggests the electrical/battery gremlins reported on X351 cars.
Get a battery and alternator health check done, even if the car starts fine. A weak battery on these cars can trigger warning lights and infotainment faults that look far worse than they are.
Run a hand along the bootlid seam, lower door edges and wheelarches for bubbling paint. Early corrosion here is a sign of stone chip damage or poor drainage that will get worse and isn't cheap to put right.

The MOT data

Measured

Computed from DVSA MOT results, all of Great Britain, 2025. Nothing here is opinion.

How this model wears

Jaguar XJClass average, all tracked models

What testers flag

Share of tests where each item was recorded. The dark tick is the class average across all tracked models; bars are scaled within each group.

Faults with the car itself

The rows that judge the model rather than its keeper. 3,416 tests in this band.

A suspension pin, bush or joint excessively worn
Advisory
7.4%class 5.9%
A spring or spring component fractured or seriously weakened
Fail
2.1%class 1.4%
Fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users
Advisory
1.8%class 2.4%
A brake hose ferrule excessively corroded
Advisory
1.5%class 0.4%
A suspension component excessively damaged or corroded
Advisory
1.3%class 0.6%
A wheel badly distorted or wear between wheel and hub at spigot mounting
Advisory
1.3%class 0.6%
A suspension pin, bush or joint excessively worn
Fail
1.0%class 0.9%
Excessive fluctuation in brake effort through each wheel revolution.
Advisory
1.0%class 0.6%
Engine MIL illuminated indicating a malfunction
Fail
0.8%class 0.4%

Wear, upkeep and luck

Tyres, pads and stone chips say more about how the car was driven and maintained than about how it was built.

Tyre tread depth not in accordance with the requirements
Advisory
33.3%class 22.9%
A tyre seriously damaged
Advisory
10.5%class 13.4%
Brake disc or drum excessively weakened, insecure or fractured
Advisory
8.1%class 10.1%
A brake lining or pad worn below 1.5mm
Advisory
6.4%class 8.7%
Tyre tread depth not in accordance with the requirements
Fail
2.1%class 2.3%
A tyre cords visible or damaged
Fail
2.0%class 1.2%
Brake disc or drum significantly and obviously worn
Advisory
2.0%class 3.4%
A tyre seriously damaged
Fail
1.7%class 1.4%

Others in its class

Same segment (Saloons & estates), best MOT record first. Compare before you shortlist.