Thinking about buying a used Lexus RX (1998–2022) in New Zealand? We've documented 26 known faults for this model spanning electrical, suspension, engine, and fluid leaks. Each researched and verified before it's published. The most serious issues here are rated critical. Two are set out in full below — the rest, with the symptoms, repair costs and checks for each, are free with an account.
26
Documented faults
Critical
Most serious
$500–$2,200
Typical repair
8
Systems covered
Known Lexus RX faults
Every fault below is documented specifically for this model — researched and verified before it’s published.
01RX400h hybrid inverter failure — sudden loss of drive
CriticalOccasionalElectrical $3,000–$6,500 to fix
The RX400h's power inverter (the electronics that drive the hybrid motors) has a documented failure pattern: transistor failure causes the car to throw hybrid warnings and go into limp mode or lose drive entirely, sometimes affecting power steering and braking assistance. Lexus extended inverter warranty coverage in some markets after complaints and lawsuits, but those programmes have expired; replacement with new parts is very expensive, though good used/reconditioned inverters bring the cost down.
Symptoms to notice
Master warning / hybrid system warning followed by loss of drive
Car cranks into 'ready' but won't move
Sudden limp mode on the motorway
Cooling fans running hard with hybrid warnings
What to check
Ask a hybrid specialist to scan for historical hybrid system codes (P0A78, P3125 etc.) before purchase. Check the inverter coolant reservoir (separate small tank) for level and cleanliness — neglected inverter coolant accelerates failure. Ask directly whether the inverter has ever been replaced.
Where to look: Inverter unit — large alloy box on top of the transaxle in the engine bay; separate inverter coolant reservoir nearby
The U660E 6-speed automatic transmission fitted to RX 350 models develops a characteristic shudder or vibration during light throttle application at highway cruise speeds, caused by degraded torque converter lock-up clutch friction material contaminating the transmission fluid. Lexus and Toyota issued guidance recommending a specific Toyota WS (World Standard) ATF change as a first corrective step; in advanced cases the torque converter requires replacement. Vehicles with infrequent or incorrect-fluid transmission services are significantly more prone to early onset.
Symptoms to notice
Shudder or vibration through the body at 70–110 km/h under light throttle cruise
Vibration disappears when accelerator is fully lifted or pressed firmly
Symptom most noticeable in 4th, 5th, or 6th gear lock-up
May be accompanied by a brief hesitation before the vibration settles
ATF fluid appears dark brown or smells burnt on inspection
What to check
During a test drive, maintain a steady light throttle at 80–100 km/h and feel for a vibration or shudder through the drivetrain lasting 1–3 seconds before the torque converter locks up cleanly. Ask when the transmission fluid was last changed and confirm Toyota WS fluid was used. Check if the fluid on the dipstick (if accessible) is dark or smells burnt.
Where to look: Transmission — torque converter lock-up clutch, accessible only with transmission removal
Ask the seller
“Has the transmission fluid ever been changed, and was Toyota WS fluid specified?”
“Have you noticed any vibration or shudder at highway speeds under light acceleration?”
“Has the vehicle had any transmission servicing or fault codes related to the gearbox?”
SuspensionCritical
EngineCritical
Fluid LeaksCritical
ElectricalMajor
EngineMajor
ElectricalMajor
EngineMajor
BrakesMajor
ElectricalMajor
TransmissionMajor
CoolingMajor
SuspensionMajor
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ElectricalMajor
EngineMajor
SuspensionMajor
EngineMajor
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ElectricalMinor
ElectricalMinor
ElectricalMinor
ElectricalMinor
InteriorCosmetic
24 more documented faults on the Lexus RX
Symptoms, what to check, where to look and what to ask the seller — for every fault above. Free with an account, no card needed. One account covers one vehicle, so make it the car you’re actually looking at.
This page covers the model. Enter the plate of the actual car you’re looking at and see its year, engine, safety rating and register flags — free, no account needed.
Like any used car, it depends on the specific example and its service history. Across the 26 documented faults for the Lexus RX, the recurring problem areas are electrical, suspension, and engine. A Lexus RX with a full service history and no signs of the issues listed on this page can be a sound buy but each one needs to be checked individually before you commit.
What are the most common problems with a used Lexus RX?
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We've catalogued 26 known faults for the Lexus RX, covering electrical, suspension, and engine. Two are written out in full on this page. The rest — with the symptoms to notice, what to inspect, and typical repair costs for each — are free once you create an account.
How much do repairs cost on a Lexus RX?
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Most single repairs on the Lexus RX fall between $500–$2,200 at NZ independent-workshop rates. Some of the 26 documented faults cost less and a few cost considerably more, and no one car needs them all. Knowing which ones to look for before you view is what lets you negotiate the price down or walk away.
Should I get a pre-purchase inspection on a Lexus RX?
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Yes. A Lexus RX inspection focused on its known weak points is the single best way to avoid an expensive mistake. KickTyres gives you a guided, model-specific inspection plus a market valuation and negotiation figure for $17.90 far less than the cost of missing one of the faults on this page.