IsItAGoodCar
Reliability Guide

Common Problems with the
2006–2009 Lexus RX (XU30)

We've identified 2 known issues that can affect the 2006–2009 Lexus RX (XU30). 1 of these are serious faults that could be expensive to repair.

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 2006–2009 Lexus RX (XU30)

  • On RX 400h hybrids, verify whether the hybrid inverter intelligent power module (IPM) recall was completed by checking dealer records or running the VIN through Lexus UK.
  • Inspect the bottom corners of the engine radiator for pink crystalline crusting; the factory Denso radiators frequently develop hairline splits along the plastic tank seams.
  • For SE-L models fitted with height-adjustable air suspension, leave the vehicle parked overnight and verify that none of the four corners drop onto their bump stops.
  • Check rear brake discs through the alloy spokes for heavy rust ridges and uneven pad contact; regenerative braking means mechanical brakes are easily neglected in wet UK winters.
  • On RX 300 and RX 400h models, ensure the timing belt and water pump have been replaced within the last 7 years or 100,000 miles, as the MZ-series V6 is an interference engine.
2005
Check a 2006–2009 Lexus RX (XU30) by Registration