Jaguar XJ MOT Failures: Common Issues & Parts Guide (X351, 2010–2019)

The Jaguar XJ X351 was a radical departure when it launched in 2010 — a full-size luxury saloon wrapped in an aluminium monocoque body that weighed less than most of its rivals. Available in standard and long-wheelbase (LWB) forms, with engines ranging from a 2.0-litre four-cylinder turbo to the thundering 5.0-litre supercharged V8 in the XJR, it remains one of the most striking executive cars of its era. But with the earliest examples now 16 years old and even the last cars past their fifth birthday, MOT failures are increasingly common. Based on DVSA anonymised data from 10,174 real MOT tests, here's exactly what's failing, why, and the parts you need.

XJ X351 MOT Pass Rate

The XJ holds an 83.3% MOT pass rate — 6.6 percentage points above the UK average of 76.7%. That's a strong result for a complex luxury car, though there's a significant spread between the oldest and newest examples — and the earliest X351s are now failing at rates above one in five.

The median mileage at MOT is 74,536 miles — lower than the XF's 106,000, reflecting the XJ's role as a prestige car rather than a daily motorway cruiser. Around 30.8% of failure items are classed as dangerous, notably higher than the XF — driven largely by tyre and brake issues on a heavy car.

1. Tyres & Wheels — The #1 Failure Category

Tyres and wheels are the single largest failure category on the XJ, accounting for 32.6% of all recorded failure items (1,100 items). Three tyre-related failures dominate the top five individual items.

What Fails

• Tyre tread depth non-compliant — 335 failures (the #2 individual item)
• Tyre cords visible or damaged — 290 failures
• Tyre seriously damaged — 241 failures
• Wheel fracture or welding defect — 54 failures (unusually high — a known X351 issue with certain alloy wheel designs)
• Loose or missing wheel nut/bolt — 50 failures

The XJ's weight (1,700–1,950 kg) and rear-wheel-drive layout wear the rear tyres significantly faster than the fronts. The staggered tyre setups on some trims (wider rears) mean rotation isn't possible. Popular 19" and 20" wheel options are more susceptible to pothole and kerb damage — and replacement tyres for these sizes are considerably more expensive than the smaller wheels fitted to the XF.

The wheel fracture count at 54 is notable. Certain OEM alloy designs are prone to cracking, particularly on cars running low-profile tyres over poor road surfaces.

What You Need

Tip: TPMS sensors are battery-powered with a 7–10 year lifespan. On an X351 of this age, most will have failed or be close to it. A persistent TPMS warning light is an MOT advisory. Budget for a full set of four when replacing.

2. Suspension — 30.8% of All Failures

Suspension is the second-largest failure category at 30.8% of all failure items (1,040 items). The X351's double-wishbone front and multi-link rear suspension delivers superb ride quality — but it has a lot of joints, bushes, and arms that degrade with age and mileage.

What Fails

• Suspension pin, bush or joint excessively worn — 345 failures (the #1 individual item across all categories)
• Spring or component fractured/weakened — 289 failures (the #4 individual item — remarkably high)
• Suspension joint dust cover missing or deteriorated — 218 failures
• Suspension component excessively damaged or corroded — 31 failures

The spring fracture count at 289 is exceptionally high for the number of tests — nearly 1 in 35 XJs tested has a fractured spring. This is a known JLR-wide issue, with rear coil springs cracking at the lowest coil due to corrosion and fatigue. The XJ's weight makes the problem worse than on lighter models.

Cars equipped with air suspension (standard on some trims, optional on others) have an additional failure vector — air springs that leak, compressors that wear out, and height sensors that corrode. A collapsed air spring is an immediate MOT failure.

What You Need

Tip: If one rear spring fractures, replace both sides. A mismatched pair causes the car to sit unevenly — an MOT advisory in itself. On air-sprung cars, a slow leak can take weeks to become obvious — if the car sits lower on one corner after standing overnight, the air spring is failing.

3. Lamps & Lighting — 11.5% of Failures

Lighting is the third-largest failure category at 11.5% of all items (387 items). The XJ's sophisticated lighting system — full LED on later models, adaptive xenon/bi-xenon on earlier cars — creates MOT exposure beyond simple bulb failures.

What Fails

• Rear registration plate lamp missing or inoperative — 102 failures (the #9 individual item)
• Headlamp cleaning device inoperative (LED/HID systems) — 74 failures
• Headlamp aim outside limits — 70 failures
• Headlamp or light source missing/inoperative — 24 failures
• Stop lamp missing or inoperative — 22 failures

The headlamp washer failure at 74 is a standout — xenon/HID-equipped XJs must have working headlamp washers to pass the MOT. A blocked jet or failed pump means the car fails regardless of headlamp condition. The adaptive headlamp system uses self-levelling that requires working sensors and motors — if the self-levelling fails, the beam pattern drifts outside limits.

What You Need

Tip: Full LED headlamp units on the later XJ cannot have individual LEDs replaced — the entire unit must be swapped. These are expensive, so check they're both working before purchasing the car.

4. Brakes — 9.7% of Failures

Brake issues account for 9.7% of all failure items (328 items). Brake pad wear is the 8th most common individual failure.

What Fails

• Brake lining/pad worn below 1.5mm — 106 failures
• Brake disc significantly worn or scored — 34 failures
• Brake pad worn to wear indicator — 31 failures
• Excessive fluctuation in brake effort — 24 failures

At nearly two tonnes, the XJ's front brakes take enormous punishment — especially the diesel models, which are heavier than the petrols. The electronic parking brake can seize if the car is left standing for extended periods, causing rear caliper binding.

What You Need

Tip: The XJ's electronic parking brake should be exercised regularly to prevent the rear calipers from seizing. A seized rear caliper is an MOT failure and an expensive repair — the caliper often needs replacing, not just freeing.

5. Windscreen Washers & Visibility — 5.4% of Failures

Visibility issues account for 5.4% of all failure items (183 items). Windscreen washer failure is the 7th most common individual MOT failure on the XJ, with 142 recorded failures.

What Fails

• Windscreen washers non-functional — 142 failures
• Wiper blade missing or not clearing windscreen — 38 failures

The heated washer jets fitted to the XJ are prone to corrosion over time, restricting flow. The wiper motors are reliable but the blade quality matters — cheap replacements often fail to clear the large windscreen adequately.

What You Need

6. Emissions, Exhaust & Engine Management — 2.7% of Failures

Emissions and exhaust issues account for 2.7% of failure items (91 items) — lower than many rivals, but the consequences of an engine management light are severe.

What Fails

• Engine MIL (management light) illuminated — 55 failures (a mandatory MOT failure since 2018)
• DPF issues (3.0 diesel)
• EGR valve clogging (3.0 diesel)
• Lambda sensor degradation (all engines)

What You Need

7. Steering — 0.4% of Failures

Steering issues are rare on the XJ at just 0.4% of failure items — but when they occur, they're significant.

What Fails

• Steering rack gaiter or ball joint dust cover deteriorated — 39 failures

The XJ uses electro-hydraulic power steering (EHPAS) on most models, which can develop leaks at the high-pressure hoses. The long wheelbase of the LWB models puts additional stress on the steering components.

What You Need

Beyond the MOT: Major XJ X351 Faults That Drive Workshop Visits

These are the issues that don't necessarily show up on an MOT but bring XJ owners into workshops — and they all need parts.

Air Suspension Failure

The XJ's optional (and on some trims, standard) air suspension is the model's single most expensive failure point. The air springs develop leaks — typically from perished rubber bellows — causing the car to drop on one corner overnight. The compressor runs overtime trying to compensate, burns out, and then the car drops completely. A full system failure can leave the car undriveable.

Early symptoms are a slight lean after standing overnight and the compressor running for longer than normal at startup. Don't ignore these signs.

Throttle Body Failure (3.0 Diesel)

The same throttle body clogging issue as the XF. The butterfly valve sticks, the engine enters "Restricted Performance" mode, and DPF regeneration can't complete — leading to a cascade of DPF blockage and further problems. A straightforward replacement once diagnosed.

Timing Chain Issues (3.0 Supercharged V6 & 5.0 V8)

The petrol engines use timing chains with tensioners and guides that wear prematurely — a known JLR design weakness. The 5.0 V8 is particularly affected, with the chain tensioner design allowing the chain to jump at start-up. A cold-start rattle and "Restricted Performance" warnings are the early signs. If the chain jumps, the engine is destroyed. Regular oil changes with the correct specification are the best preventative measure.

Timing Belt (3.0 Diesel)

The 3.0 V6 diesel uses a timing belt with a replacement interval of every 7 years or 112,000 miles. Given the age of these cars, many are now past their second belt change interval. The consequences of failure are catastrophic — pistons hit valves, and the engine is beyond economical repair.

Water Pump & Coolant Pipe Failures (3.0 SC V6 & 5.0 V8)

The same cooling system weakness as the XF's supercharged engines. Coolant enters the water pump bearing housing and corrodes the bearing from within. Low coolant warnings and a weep around the pump pulley are the early signs. The plastic coolant crossover pipe and multiple connectors become brittle with age and heat cycling — when one fails, replace them all. The XJ's engine bay is tighter than the XF's due to the bonnet line, making access more difficult and labour costs higher.

Crankshaft Failure (3.0 V6 Diesel)

The most catastrophic failure on the diesel XJ. The 3.0 V6 diesel can suffer crankshaft problems ranging from spun bearings to complete crankshaft failure. The engine is beyond economical repair at that point — typically requiring a replacement unit. Regular oil changes with the correct specification and monitoring oil pressure are essential.

ZF 8-Speed Gearbox Issues

The ZF 8HP automatic develops shifting problems characterised by jerky gear changes, delayed reactions, and hesitation when pulling away. Degraded fluid and sticking solenoids are the common causes. Despite Jaguar's "lifetime fill" claim, specialists recommend changing the gearbox fluid every 60,000–80,000 miles. On the 5.0 V8 models, the torque converter can also develop issues — shuddering at low speed is the telltale sign.

Electrical Cascading Faults & Battery Drain

The XJ is one of the most electrically complex cars in the JLR range, with up to 80 ECUs networked across the car. A weak battery triggers cascading warning lights across ABS, brake assist, tyre pressure, stability control, and air suspension — which can look like catastrophic multi-system failure but is often resolved by replacing the battery.

The XJ is also prone to parasitic battery drain, particularly from the infotainment system failing to enter sleep mode. A car that's flat after standing for 3–4 days typically has a drain issue rather than a dead battery.

Door Handle Microswitch Failure

The XJ's flush door handles use a microswitch to detect the touch input. These fail with age — the handle doesn't respond to touch, leaving you unable to open the door from outside. The door latch mechanism itself can also fail, causing central locking issues.

Window Regulator Failure

Electric window regulators are a common failure — the cable mechanism frays or the motor burns out. A window that won't close is both a security issue and an MOT concern if it affects the driver's visibility or ability to signal.

Inlet Manifold & Rocker Cover Leaks (3.0 Diesel)

The plastic inlet manifold on the 3.0 diesel is prone to cracking, and rocker cover gaskets leak with age. Both cause oil contamination and trigger "Restricted Performance" warnings.

XJ X351 MOT Failure Summary — At a Glance

Keeping Your Jaguar XJ on the Road

The XJ X351 is one of the great luxury saloon bargains — aluminium construction means no corrosion (structure & body failures are just 0.3% of the total), the interior is genuinely special, and the driving experience remains impressive. Its 83.3% pass rate beats the UK average comfortably, and the 2017–2019 models are passing at over 89%.

The biggest MOT risks are tyres and suspension — together they account for nearly two-thirds of all failures. Spring fractures are disproportionately common, and the wheel fracture count suggests careful attention to alloy condition. The model-specific workshop risks are air suspension failure (if equipped), the cooling system weaknesses on the supercharged petrol engines, and the timing belt/crankshaft issues on the 3.0 diesel.

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Service & Maintenance Parts

Servicing is everything on the XJ. Oil quality directly affects timing chain life on the petrol engines and timing belt life on the diesel. Gearbox fluid should be changed every 60,000–80,000 miles despite the "lifetime fill" claim. And on air-suspended cars, the compressor relay should be checked at every service.

Data sourced from DVSA anonymised MOT test results (2024 test year, 10,174 tests on X351-era Jaguar XJ models with first use dates 2010–2019). 3,375 individual failure items analysed. Specialist fault data from K Motors and Jaguar workshop reporting.