DTC P0030: Front Ho2S Heater Control Circuit Problem

Fig 1: DTC P0030 Detection Condition & Possible Causes Chart

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Diagnostic Procedure 

Fig 2: DTC P0030 Diagnostic Procedure Chart (Steps 1-7)

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Fig 3: DTC P0030 Diagnostic Procedure Chart (Step 8)

Courtesy of MAZDA MOTORS CORP.