Generations
XE10 — First Generation IS300
1999–2005
3.0 Straight-Six
Top issues to watch for
The most serious Lexus Is300 problems ranked by severity. We track 5 known issues — here are the ones you need to know about first.
Dangerous
Subframe mounting point corrosion (XE10)
The rear subframe mounting points on XE10 IS300 models are vulnerable to corrosion where the subframe bolts attach to the body shell. This affects the prescribed areas within 30cm of suspension mounting points that carry structural loads. UK examples show significantly elevated failure rates at MOT due to weakened load-bearing structure around these critical mounting points. The corrosion typically starts from inside the body cavity and progresses outward, making early detection difficult without lifting the vehicle.
What happens if ignoredIf the subframe mounting points fail completely, the rear suspension geometry becomes unstable and the car is unsafe to drive. Repair typically requires cutting out corroded sections and welding in new metal, often costing £800-£2,000 depending on the extent of the corrosion. This is an MOT failure and the vehicle cannot be used until repaired.
Independent garage
£800–£1,500
Specialist
£1,000–£2,000
Main dealer
£1,500–£3,000
Parts only
£100–£300
Major
Suspension component corrosion (XE10)
XE10 IS300 models show elevated MOT failure rates for suspension component corrosion, particularly affecting the rear suspension arms and subframe components. The combination of UK weather conditions and road salt causes accelerated corrosion of steel suspension components. This model shows failure rates nearly 7 times higher than the fleet average, indicating a particular vulnerability in the suspension design or material specification.
What happens if ignoredCorroded suspension components can fail suddenly, affecting handling and safety. Depending on which components are affected, repair costs range from £200-£800 for individual arms to over £1,500 if multiple components need replacement. Failed suspension components are an MOT failure.
Independent garage
£200–£800
Specialist
£300–£1,000
Main dealer
£500–£1,500
Parts only
£100–£400
Major
Body shell structural corrosion (XE10)
XE10 IS300 models show significantly higher rates of structural body corrosion that reduces the rigidity of the vehicle assembly. This typically affects sill areas, floor pan sections, and other load-bearing body structure, particularly where water can collect or road salt accumulates.
What happens if ignoredStructural corrosion affects the safety and rigidity of the vehicle. Minor repairs may be possible with welded patches, but extensive corrosion can make the car uneconomical to repair. Costs range from £500 for localised welding to £3,000+ for extensive structural work. This is an MOT failure category.
Independent garage
£500–£2,000
Specialist
£800–£2,500
Main dealer
£1,200–£4,000
Parts only
£50–£200
Major
Brake caliper binding (XE10)
XE10 IS300 models show elevated MOT failure rates for binding brakes, with failure rates 2.3 times higher than the fleet average. This typically affects the brake calipers, particularly the rear sliding calipers which are prone to seizing on their guide pins due to corrosion and brake fluid contamination. The issue is exacerbated by infrequent brake fluid changes and UK road conditions.
What happens if ignoredBinding brakes cause uneven tyre wear, reduced fuel economy, and can lead to brake disc and pad damage. If severe, a binding brake can cause loss of braking efficiency and dangerous handling characteristics. Repair typically involves caliper rebuild or replacement, costing £150-£400 per corner.
Independent garage
£150–£300
Specialist
£200–£400
Main dealer
£300–£600
Parts only
£80–£200
1 more known issues tracked
Including wear items, electrical niggles, and generation-specific problems.
MOT failure hotspots
Based on DVSA MOT test data. These are the items where the Lexus Is300 fails at a significantly higher rate than the average car.
Suspension pin, bush or joint worn
Suspension · 80-100k miles
MOT failure rate: 13x the fleet average
Sample: 333 tests
Subframe bushes or mounts worn
Suspension · 150k+ miles
MOT failure rate: 8.1x the fleet average
Sample: 852 tests
Power steering fault
Steering · 120-150k miles
MOT failure rate: 7.4x the fleet average
Sample: 405 tests
Suspension component damaged or corroded
Suspension · 60-80k miles
MOT failure rate: 6.9x the fleet average
Sample: 440 tests
Headlight fault
Lights & Electrics · 60-80k miles
MOT failure rate: 6.6x the fleet average
Sample: 318 tests
Structural corrosion
Bodywork · 100-120k miles
MOT failure rate: 6.0x the fleet average
Sample: 483 tests
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Related
Lexus Is300 reliability FAQs
What are the most common problems with the Lexus Is300?
The Lexus Is300 has 5 known issues across 3 severity levels. The most serious are: Subframe mounting point corrosion (XE10).
Is the Lexus Is300 reliable?
The Lexus Is300 has 1 dangerous and 3 major known issues. Most can be avoided with a thorough pre-purchase check and full service history.
How much does it cost to fix Lexus Is300 problems?
Repair costs range widely. The most significant issue (Subframe mounting point corrosion (XE10)) costs £800–£1,500 at an independent garage. Minor issues can be under £200. Always get a full inspection before buying.