One problem related to gas recirculation valve (egr valve) has been reported for the 2009 Toyota Highlander. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2009 Toyota Highlander based on all problems reported for the 2009 Highlander.
Oil cooler connected to engine block with a rubber hose. Hose failed with oil leak which caused loss of engine oil. Car towed and repaired before engine seized. It appears rubber hose was not protected from heat of catalytic converter and rubber degraded. Vehicle was in motion on interstate highway when first noticed loss of oil pressure. Added oil but oil loss continued. When warning light went on second time stopped vehicle and towed to service. Event occurred on may 15, 2020.