DTC P0037: Rear Ho2S Heater Control Circuit Low

Fig 1: DTC P0037 Detection Condition & Possible Causes Chart

Courtesy of MAZDA MOTORS CORP.

Diagnostic Procedure 

Fig 2: DTC P0037 Diagnostic Procedure Chart (Step 1-3)

Courtesy of MAZDA MOTORS CORP.

Fig 3: DTC P0037 Diagnostic Procedure Chart (Step 4-8)

Courtesy of MAZDA MOTORS CORP.