IsItAGoodCar
Reliability Guide

Common Problems with the
2005 Lexus RX (XU30)

Introduction of the landmark RX 400h in 2005, combining a 3.3-litre V6 petrol engine with Lexus Hybrid Synergy Drive and E-Four electric rear axle. In 2006, the RX 350 replaced the RX 300 with a chain-driven 3.5-litre 2GR-FE V6.

What changed for 2005

  • •Launch of the RX 400h hybrid delivering 268bhp combined output and sub-200g/km CO2
  • •E-Four electric all-wheel-drive system eliminating mechanical centre propshaft on hybrids
  • •2006 introduction of the 272bhp 3.5-litre 2GR-FE V6 with timing chain in the RX 350

Common MOT watch-outs

  • !Corroded rear brake discs and seized guide pins common across hybrid variants
  • !Headlamp aim defect or cloudy polycarbonate lenses on early xenon assemblies
  • !Air suspension leakage causing uneven axle ride height on SE-L models
2
Known Issues
1
Serious
1
Moderate
0
Minor

All Known Issues

Hybrid Inverter Intelligent Power Module (IPM) Solder Fatigue

SeriousElectrics & Electronics

On RX 400h models, the solder joints on the transistors within the Intelligent Power Module (IPM) of the hybrid inverter can fail under thermal cycling. This triggers the Check Hybrid System warning, illuminates master warning lamps, and forces the vehicle into limp-home mode or causes an immediate loss of motive power. While covered by major UK safety recalls (DVSA recalls R/2011/076 and R/2013/088), unserviced or second-hand replacement inverters can still fail if the inverter cooling system is degraded.

Est. Repair Cost: £800–£2,500
Warning Signs:

Check Hybrid System message displayed on the multi-information display, Amber master triangle warning light illuminated on the instrument cluster, Sudden loss of motive power and vehicle entering failsafe limp-home mode, Diagnostic trouble codes P0A94 (DC-DC Converter Performance) or P0A7A stored

What to Inspect:
  • Inspect Lexus UK service records to verify recall R/2011/076 or R/2013/088 was completed
  • Look into the hybrid inverter coolant expansion tank to verify active coolant turbulence with ignition in READY mode
  • Check that the inverter auxiliary electric water pump is humming quietly and not vibrating or seized
Verified by IsItAGoodCar Research TeamUpdated

Radiator End-Tank Seam Splitting and Coolant Loss

ModerateCooling System

The original Denso radiators fitted to the XU30 series suffer from age-related embrittlement of the plastic side/bottom end tanks and crimped aluminium core seams. In the UK climate, repeated thermal cycling and road salt spray accelerate corrosion along the bottom core channel, leading to slow weeping of Toyota Super Long Life pink coolant. If left unnoticed, the gradual loss of coolant can cause severe engine overheating and cylinder head gasket failure on the 3.0, 3.3, and 3.5-litre V6 engines.

Est. Repair Cost: £350–£700
Warning Signs:

Sweet coolant smell noticeable from the front grille after driving, Gradual drop in engine coolant expansion tank level over several hundred miles, Pink crusted residue or wet staining along the lower radiator tank crimp, Engine temperature gauge creeping above midpoint under motorway load

What to Inspect:
  • Shine a torch through the lower front bumper aperture to inspect the bottom radiator tank for pink crusting
  • Check the coolant expansion tank cold level and verify fluid is clean translucent pink
  • Inspect the under-engine splash shield for dried pink coolant staining or active drips
Verified by IsItAGoodCar Research TeamUpdated

Buying Tips for 2005 Lexus RX (XU30)

  • Check inverter coolant level and verify active circulation through the expansion tank neck
  • Scan for hybrid diagnostic trouble codes and confirm auxiliary 12V battery health
20042006–2009
Check a 2005 Lexus RX (XU30) by Registration