DTC P2257: Front Ho2S Signal Stuck Rich

Fig 1: DTC P2257 Detection Condition & Possible Causes Chart

Courtesy of MAZDA MOTORS CORP.

Diagnostic Procedure 

Fig 2: DTC P2257 Diagnostic Procedure Chart (Step 1-2)

Courtesy of MAZDA MOTORS CORP.

Fig 3: DTC P2257 Diagnostic Procedure Chart (Step 3-10)

Courtesy of MAZDA MOTORS CORP.