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Home >> Toyota >> 2003 >> Highlander Base, 2.4 D, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self Diagnostics - 4-Cylinder >> Diagnostic Tests >> DTC P0420: Catalyst System Efficiency Below Threshold (Bank No. 1) & DTC P0430: Catalyst System Efficiency Below Threshold (Bank No. 2) >> Circuit Description & Possible Causes
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Circuit Description & Possible Causes

For circuit description and possible causes, see Fig 1.

Fig 1: DTCs P0420 & P0430 Circuit Description & Possible Causes
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