DTC P0038: Rear Ho2S Heater Control Circuit High

Fig 1: DTC P0038 Detection Condition & Possible Causes Chart

Courtesy of MAZDA MOTORS CORP.

Diagnostic Procedure 

Fig 2: DTC P0038 Diagnostic Procedure Chart (Step 1-3)

Courtesy of MAZDA MOTORS CORP.

Fig 3: DTC P0038 Diagnostic Procedure Chart (Step 4-10)

Courtesy of MAZDA MOTORS CORP.